Prevenative dental hard tissue laser treatment systems and methods

ABSTRACT

In one aspect, embodiments relate to a system for preventative dental laser treatment that ensures even irradiation of a laser beam. The system includes, a laser arrangement configured to generate the laser beam. The laser beam has one or more of a super-Gaussian energy profile and a transverse ring mode. The system also includes a focus optic. The focus optic is configured to converge the laser beam with a numerical aperture of 0.1 or less to a focal region. The system also includes a hand piece configured to direct the laser beam at a surface of a dental hard tissue. The system additionally includes a controller. The controller is configured to control one or more parameters of the laser source, such that a portion of the surface of the dental hard tissue is heated to a temperature in a range between 400° Celsius and 1300° Celsius.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to PCT App. No.PCT/US21/15567, filed on Jan. 28, 2021 and entitled “PREVENTATIVE DENTALHARD TISSUE LASER TREATMENT SYSTEMS, METHODS, AND COMPUTER-READABLEMEDIA,” the entirety of which is incorporated herein by reference. PCTApp. No. PCT/US21/15567 in turn claims priority benefit to U.S. Prov.App. No. 62/969,115, filed on Feb. 2, 2020 and entitled “SYSTEMS ANDMETHODS FOR DISTRIBUTION OF SINGLE USE PREVENTATIVE DENTAL HARD TISSUETREATMENTS,” U.S. Prov. App. No. 62/968,910, filed on Jan. 31, 2020 andentitled “LASER DELIVERY OF TRANSVERSE ELECTROMAGNETIC MODES FOR EVENPREVENTATIVE DENTAL HARD TISSUE TREATMENT,” U.S. Prov. App. No.62/968,922, filed on Jan. 31, 2020 and entitled “CONTACT COUPLEDDELIVERY OF RADIATION FOR DENTAL HARD TISSUE TREATMENT,” all of whichare incorporated herein in their entirety by reference.

TECHNICAL FIELD

This invention generally relates to systems and methods for preventativedental laser treatment and, more particularly but not exclusively, tosystems and methods for delivery of laser beams with certain transverseelectromagnetic modes during dental treatment.

BACKGROUND

Research has long showed the ability of some lasers to make dental hardtissue (e.g., enamel) less susceptible to acidic dissolution. Forexample, in 1998, J. Featherstone et al. demonstrated inhibition ofcaries progression ranging from 40% to 85% after irradiation withinfrared laser sources in an article entitled “CO₂ Laser Inhibitor ofArtificial Caries-Like Lesion Progression in Dental Enamel,”incorporated herein by reference, published in the Journal of DentalResearch. These results have been corroborated and repeated throughoutthe years. Another notable project involved researchers for Universityof California San Francisco and Indiana University both evaluating lasertreatment for caries-inhibition in different intra-oral models. Theproject was documented in an article entitled “Effect of Carbon DioxideLaser Treatment on Lesion Progression in an Intraoral Model,” publishedin 2001 in Proc. SPIE by J. Featherstone et al. and incorporated hereinby reference.

A mechanism that is believed to contribute to this inhibition of aciddissolution in laser treated hard tissue is carbonate removal. Humandental enamel is primarily (96%) comprised of hydroxyapatite (HA).Specifically, the HA found in dental enamel is non-stoichiometriccarbonate-substituted hydroxyapatite(Ca₁₀(PO₄)_(6−x)(OH)_(2−y))(CO₃)_(x+y), where 0≤x≤6, 0≤y≤2, whichcontains trace amounts of fluoride (F), sodium (Na), magnesium (Mg),zinc (Zn) and strontium (Sr)), as reported by C. Xu et al., in anarticle published in 2014 in J. Material Sci., entitled “TheDistribution of Carbonate in Enamel and its Correlation with Structureand Mechanical Properties,” incorporated herein by reference. Xu et al.describe that increases in carbonate content within enamel correlatewith decreases in mechanical properties, for example crystallinity,modulus, and hardness. It has also been long reported that increasedcarbonate content within enamel correlates with an increasedsusceptibility to acid. For example, J. Featherstone et al. reported in“Mechanism of Laser-Induced Solubility Reduction of Dental Enamel,”first published in SPIE Proc. in 1997, incorporated herein by reference,that carbonate removal from enamel correlates to increased resistance tocaries, with complete carbonate removal correlating with the optimumresistance to caries. Caries are formed by acid dissolution ordemineralization. Removal of carbonate within dental enamel is achievedthrough elevating a temperature of the enamel.

The temperature range required for removing carbonate from dental tissuehas long been taught, for example by Zuerlein et al. in an article,published in 1999 in Lasers in Surgery and Medicine, entitled “Modelingthe Modification Depth of Carbon Dioxide Laser-Treated Dental Enamel”and incorporated herein by reference. Zuerlein et al. found thatcarbonate loss began when enamel reached temperatures in excess of 400°C. during laser irradiation, but complete carbonate removal was notachieved until the enamel reached its melting point. The melting pointof dental enamel is about 1280° C. as reported by Fried et al. in anarticle, published in 1998 in Applied Surface Science, entitled “IRLaser Ablation of Dental Enamel: Mechanistic Dependence on the PrimaryAbsorber,” incorporated herein by reference.

For over 20 years it has been known to the dental research communitythat momentarily elevating a temperature of dental enamel to temperaturein a range between 400° C. and 1300° C. will reduce carbonate contentand increase the enamel's resistance to acid (e.g., caries and erosion).However, the difficulties associated with momentarily raising apatient's tooth surface to a temperature more consistent with that ofliquid magma (e.g., lava) than human tissue, presents a number ofproblems, which have yet to be satisfied in a commercial product.

SUMMARY

While the results of the scientific research have shown great promisefor over 20 years, careful scrutiny of the literature will reveal, inmost cases (with a few notable exceptions), that after undergoing laserirradiation, dental hard tissue surfaces are often damaged by the laser.Commonly, much of the surface of the dental hard tissue will melt,crack, or partially ablate as a result of overheating during treatment,or sections of the enamel are unknowingly left untreated due to thetreatment parameters variability. This typically does not negativelyaffect most acid dissolution (e.g., caries inhibition) measurements, butit nevertheless remains an undesirable result of treatment.

As mentioned above, some references in the literature have taken specialcare not to cause melting or cracking of dental hard tissue duringpreventative laser treatment. These references are pointed out below. M.Esteves-Oliveira et al. describe achieving caries resistant effectswithout thermal damage in “CO₂ Laser (10.6 μm) Parameters for CariesPrevention in Dental Enamel,” published in Caries Research andincorporated herein by reference. J. W. Kim et al. also demonstratedthat lower fluences can cause acid resistance in teeth without alsomelting or cracking in “Influence of a Pulsed CO₂ Laser Operating at 9.4μm on the Surface Morphology, Reflectivity, and Acid Resistance ofDental Enamel Below the Threshold for Melting,” published in the Journalof Biomedical Optics in 2017 and incorporated herein by reference. Both,J. W. Kim et al. and M. Esteves-Oliveira et al. demonstrate that it ispossible in vitro to induce acid dissolution resistance in an enamelsurface without also melting the enamel using a CO₂ laser with aGaussian energy profile, however additional problems are presented byattempts to commercialize the technology. For example, how to ensurethat the enamel is never overheated in tens of thousands of treatments?

Some recent steps have been made toward addressing these problems forpotential commercialization. For example, U.S. patent application Ser.No. 15/976,272 by Groves et al., incorporated herein by reference,describe a laser system for preventative dental hard tissue treatment.Specifically, Groves et al. describes controlling a CO₂ laser beam pulseenergy in order to deliver a controlled amount of energy (e.g., not toomuch energy), to prevent surface modifications (defined within theapplication to mean cracking or melting) while still achieving atherapeutic effect. In order to achieve this Groves et al. describe anumber of power and energy feedback systems that measure pulsed laserenergy interpulse and intrapulse. Real-time (e.g., less than 500 nS)measurement of infrared (e.g., wavelength of 8 μm or greater) laserenergy requires use of specialized photodiodes (e.g., Mercury CadmiumTelluride [HgCdTe] sensors). Additionally, these photodiodes onlyprovide a relative intrapulse measurement of laser power. Therefore, thesystems must be calibrated by the user (e.g., before every treatment),typically with a thermopile to measure absolute average power of thelaser beam. Thermopiles are notoriously inaccurate and typically providea measurement that is within a range of +/−5% of actual laser power.Additionally, CO₂ lasers drift in power output during normal operation,in a range of about +/−10%. With so many sources of uncertainty, precisecontrol of pulse energy is imperfect in a commercially realizabledevice. It is for this reason that systems like those described byGroves et al. must reduce the peak irradiance (or fluence) delivered tothe dental hard tissue and produce non-optimal heating of dental tissuein order to ensure that overheating does not occur. Exemplarynon-optimal results are shown by Groves et al. in FIGS. 7C and 7D, whichindicate incomplete carbonate removal of the treated surface.

Additionally, unlike many of the tools presently used in dentaloperatories, Groves et al. describe a system that must use anon-contacting dental laser hand piece. The hand piece must be used by adental clinician to aim a laser beam at every tooth surface undergoingtreatment. This places a large burden on the dental clinician toaccurately aim the laser, treat the enamel surfaces (without missing aspot), avoid hitting unintended oral surfaces with the laser, and do allof this quickly (with as little “patient chair time” as possible). Asystem as taught by Groves et al., if realizable in a commercialproduct, would require substantial amounts of training on the part ofthe dental clinician prior to proficient use of the system.

While the results of the scientific research have shown great promisefor over 20 years, commercialization and adoption of this technology hasnot occurred anywhere in the world. A commercial impediment to theadoption of this groundbreaking technology is the relatively high costof mid-infrared (e.g., wavelength between 9 and 11 μm) laser sources andother high-tech components (e.g., optical components, beam scanningsystems, and articulated arms) required to perform the laser treatment.For example, at the time of writing the Solea dental laser system (fromConvergent Dental of Needham, Mass., U.S.A.) which is not FDA clearedfor preventative dental laser treatment, but which does comprise amid-infrared laser source costs over $120,000. This high price point iscommonplace for medical and dental systems that employ laser sources andtypically prices adoption of these systems out of reach of medical anddental practitioners that do not place a high premium on using thelatest technology.

Systems and methods for preventative dental laser treatment have beenknown to science for decades. However, the known state-of-the-art(including all of the above mentioned references) fail to (i) produce alaser beam that optimally heats the enamel, without generating centralareas of peak temperature that are prone to overheating; (ii) a systemthat may be used in contact with the laser tissue, like tools alreadyknown to dental hygienists and dentists; or, (iii) teach a way for therequired high tech (and high cost) technology to be implemented inordinary dental operatories and thereby be made accessible to all dentalpatients, without great upfront investment being required by individualdental practitioners. In order for dental patients to benefit fromdecades of scientific breakthroughs in preventative dental lasertreatments, laser systems and methods must be developed that (i)reliably introduce even heating of the dental hard, while simultaneouslypreventing overheating; (ii) are easily adopted and quickly and safelyused by dental clinicians; and, (iii) can be made available with a coststructure, which the dental market can comfortably bear.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription section. This summary is not intended to identify or excludekey features or essential features of the claimed subject matter, nor isit intended to be used as an aid in determining the scope of the claimedsubject matter.

In one aspect, embodiments relate to a system for preventative dentallaser treatment that ensures even irradiation of a laser beam. Thesystem includes, a laser arrangement configured to generate the laserbeam. The laser beam has at least one of a super-Gaussian energy profileand a transverse ring mode. The system also includes a focus optic. Thefocus optic is configured to converge the laser beam with a numericalaperture of 0.1 or less to a focal region. The system also includes ahand piece configured to direct the laser beam at a surface of a dentalhard tissue. The system additionally includes a controller. Thecontroller is configured to control at least one parameter of the lasersource, such that a portion of the surface of the dental hard tissue isheated to a temperature in a range between 400 and 1300° Centigrade.

In some embodiments of the system, the system also includes a turningmirror positioned down beam from the focus optic. The turning mirror isconfigured to reflect the laser beam toward the dental hard tissue.

In some embodiments of the system, the laser arrangement includes a beamshaper. The beam shaper is configured to shape the laser beam into theat least one of the super-Gaussian energy profile and the transversering mode. In some versions, the beam shaper includes at least one of anaxicon, a spatial filter, a deformable mirror, and an annular slit.

In some embodiments of the system, the laser beam has a wavelength in atleast one of a first range of 200 to 500 nm and a second range of 4,000to 11,000 nm.

In some embodiments of the system, the laser arrangement also includesat least one of an intra-cavity polarization generator and apolarization converter. In some cases, the laser beam has a polarizationthat comprises at least one of circular, radial, tangential, andazimuthal.

In some embodiments of the system, the at least one laser parameter ofthe laser beam controlled by the controller includes at least one of:repetition rate, pulse energy, pulse duration, average power, peakpower, and wavelength.

In some embodiments of the system, the system additionally includes abeam scanning system. The beam scanning system is configured to scan thefocal region over a portion of the surface of the dental hard tissue.

In some embodiments of the system, the transverse ring mode has an innerdiameter that is 50% less than its outer diameter.

In some embodiments of the system, the transverse ring mode is atransverse electromagnetic mode (TEM) 01*.

In some embodiments of the system, the focus optic has a focal lengththat is greater than 100 mm.

In some embodiments of the system, the laser arrangement includes alaser source having an intra-cavity device configured to generate the atleast one of the super-Gaussian energy profile and the transverse ringmode.

In some embodiments of the system, the laser arrangement includes alaser source having an intra-cavity device configured to control a powerof the laser beam.

In another aspect, embodiments relate to a method for preventativedental laser treatment that ensures even irradiation of a laser beam.The method includes generating, using a laser arrangement, a laser beamhaving at least one of a super-Gaussian energy profile and a transversering mode; converging, using a focus optic, the laser beam with anumerical aperture no greater than 0.1 to a focal region; directing,using a hand piece, the laser beam at a surface of a dental hard tissue;and, controlling, using a controller, at least one parameter of thelaser beam, such that a portion of the surface of the dental hard tissueis heated to a temperature in a range of 400 to 1300° C.

In some embodiments of the method, the method also includes reflecting,using a turning mirror, the laser beam toward the dental hard tissue.The turning mirror is located down beam from the focus optic.

In some embodiments of the method, generating the laser beam having theat least one of the super-Gaussian and the transverse ring mode includesshaping, using a beam shaper, the laser beam. In some versions, the beamshaper includes one or more of an axicon, a spatial filter, a deformablemirror, and an annular slit.

In some embodiments of the method, the laser beam has a wavelength in atleast one of a first range of 200 to 500 nm and a second range of 4,000to 11,000 nm.

In some embodiments of the method, the laser arrangement also includesat least one of an intra-cavity polarization generator and apolarization converter. In some cases, the laser beam has a polarizationthat comprises at least one of circular, radial, tangential, andazimuthal.

In some embodiments of the method, the at least one parameter controlledby the controller is at least one of: repetition rate, pulse energy,pulse duration, average power, peak power, and wavelength.

In some embodiments of the method, the method also includes scanning,using a beam scanning system, the focal region over a portion of thesurface of the dental hard tissue.

In some embodiments of the method, the transverse ring mode has an innerdiameter that is 50% less than its outer diameter.

In some embodiments of the method, the transverse ring mode is atransverse electromagnetic mode (TEM) 01*.

In some embodiments of the method, the focus optic has a focal lengththat is greater than 100 mm.

In some embodiments of the method, the laser arrangement includes alaser source having an intra-cavity device configured to generate thetransverse ring mode.

In some embodiments of the method, the laser arrangement includes alaser source having an intra-cavity device configured to control a powerof the laser beam.

In one aspect, embodiments relate to a system for preventativeirradiative dental treatment. The system includes, a radiation sourceconfigured to generate a radiation. The radiation has a wavelengthwithin one of two ranges, a first range of 100-500 nm and a second rangeof 8,000-12,000 nm. The system also includes an optic disposed to acceptthe radiation at a first end, internally reflect the radiation, andcontact a dental hard tissue with at least one side of the optic. Theoptic is additionally configured to couple at least a portion of theradiation into the dental hard tissue when placed in contact with thedental hard tissue on the at least one side. The system also includes acontroller configured to control at least one parameter of the radiationto heat a surface of the dental hard tissue to a temperature of at least400° Celsius.

In some embodiments of the system, the optic comprises one or more of awaveguide, a rod, and a prism.

In some embodiments of the system, the optic has an index of refractionthat is no greater than an index of refraction of the dental hard tissueand no less than an index of refraction of a dental soft tissue.

In some embodiments of the system, the optic is configured to couple atleast a portion of the radiation into the dental hard tissue using atleast one of attenuated total internal reflection (ATIR), frustratedtotal internal reflection (FTIR), and an evanescent wave.

In some embodiments of the system, the optic is additionally configuredto couple substantially no portion of the radiation into a dental softtissue when placed in contact with the dental soft tissue on the atleast one side.

In some embodiments of the system, the optic is further configured to beplaced in contact with an inter-proximal surface of the dental hardtissue.

In some embodiments of the system, the optic includes at least one ofquartz, zinc sulfide, barium fluoride, magnesium fluoride, calciumfluoride, zinc selenide, and diamond.

In some embodiments of the system, the system additionally includes adetector configured to detect at least one characteristic of theradiation as it exits a second end of the optic.

In some embodiments of the system, the system additionally includes acooling system configured to cool the optic.

In some embodiments of the system, the system additionally includes ahomogenizer disposed between the radiation source and the optic tohomogenize the radiation.

In another aspect, embodiments relate to a method for preventativeirradiative dental treatment. The method includes generating, using aradiation source, a radiation having a wavelength within one of tworanges, a first range between 100 and 500 nm and a second range between8,000 and 12,000 nm; internally reflecting the radiation within an opticdisposed to accept the radiation at a first end; contacting a dentalhard tissue with at least one side of the optic; coupling, using theoptic, at least a portion of the radiation into the dental hard tissue;and, controlling, using a controller at least one parameter of theradiation to heat a surface of the dental hard tissue to a temperatureof at least 400° Celsius.

In some embodiments of the method, the optic comprises one or more of awaveguide, a rod, and a prism.

In some embodiments of the method, the optic has an index of refractionthat is no greater than an index of refraction of the dental hard tissueand no less than an index of refraction of a dental soft tissue.

In some embodiments of the method, coupling, using the optic, at least aportion of the radiation into the dental hard tissue includes at leastone of attenuated total internal reflection (ATIR), frustrated totalinternal reflection (FTIR), and an evanescent wave.

In some embodiments of the method, the method additionally includescontacting a dental soft tissue with the at least one side of the optic;and, coupling, using the optic, substantially no portion of theradiation into the dental soft tissue.

In some embodiments of the method, the method additionally includescontacting, using the optic, an inter-proximal surface of the dentalhard tissue.

In some embodiments of the method, the optic includes at least one ofquartz, zinc sulfide, zinc selenide, barium fluoride, magnesiumfluoride, calcium fluoride, sapphire, and diamond.

In some embodiments of the method, the method also includes detecting,using a detector, at least one characteristic of the radiation as itexits a second end of the optic.

In some embodiments of the method, the method also includes cooling theoptic, using a cooling system.

In some embodiments of the method, the method also includes homogenizingthe radiation, using a homogenizer.

As disclosed above, much research has been done on the use of a laserfor affecting an increase in acid resistance in dental hard tissue.However, acquiring a laser system typically requires dental practices topay an expensive upfront cost ($50,000 or more). The high upfront costof the laser system is expected to slow the adoption of this potentiallyparadigm shifting technology. Furthermore, it is expected that becauseof this high upfront cost dental practices treating patients most likelyto benefit from the treatment (e.g., patients from communities havingworse dental hygiene), in some cases, will be last to gain access tothis laser technology. In order to speed adoption of this remarkabletechnology and combat this access problem new systems and methods forpreventative laser treatment distribution are disclosed.

In accordance with one embodiment, an upfront cost of a dental lasersystem is partially defrayed after installation of the laser system bysmall recurring costs. For example, in some versions a dental lasersystem is provided at a reduced cost to a dental practice (minimizingupfront costs) and the dental practice pays small recurring payments touse the dental laser system. In some cases, the recurring payments aremade on a subscription basis (e.g., per day, per week, per month, or peryear). Alternatively, the recurring payments are made per treatment (orper a certain number of treatments).

Commercially, a reduction in price of a high-tech laser system cannot bewarranted unless recurrent sales are virtually guaranteed to the dentallaser system manufacturer. Unfortunately, unauthorized use is possibleeither by unknowing clinicians who fall victim to counterfeiters, or byfraudulent users. Unauthorized use of the laser system (withoutrecurrent payment), therefore poses a threat to the recurrent paymentdistribution method and therefore to the widespread adoption ofpreventative dental laser treatment. At least for these reasons,embodiments of systems and methods are presented herein that aim toprevent and expose unauthorized use of a preventative dental lasersystem.

In one aspect, embodiments relate to a method for preventative dentallaser treatment. The method includes a reading a machine-readable code;verifying, using a processor, the machine-readable code; performing alaser treatment, based upon the verified machine-readable code; applyinga dental fluoride treatment dose; and, preventing, using the processor,future verification of the machine-readable code. Performing the lasertreatment includes generating, using a laser arrangement, a laser beam;directing, using an optical arrangement, the laser beam toward a dentalhard tissue; and, controlling, using a laser controller, a parameter ofthe laser beam in order to heat at least a portion of a surface of thedental hard tissue to a temperature above 400° Celsius.

In some embodiments of the method, the dental fluoride dose comprisesone or more of Sodium Fluoride, Stannous Fluoride, TitaniumTetrafluoride, Acidulated-Phosphate Fluoride, and Amine Fluoride.

In some embodiments of the method, the dental fluoride dose comprisesone or more of a gel, a varnish, a paste, and a foam.

In some embodiments of the method, the machine-readable code comprisesone or more of a barcode, a two-dimensional (2D) barcode, a data matrix,a digital signature, a cryptocurrency, a magnetic strip, a transponderdevice, a microchip, and a radio-frequency identification (RFID) tag.

In some embodiments of the method, verifying the machine-readable codeincludes one or more of querying a ledger; broadcasting to a ledger;decrypting the machine-readable code; recognizing a digest within themachine-readable code; querying a write once read many (WORM) memory;and, querying a coupon authority.

In some embodiments of the method, preventing future verification of themachine-readable code includes one or more of broadcasting to a ledger;submitting to a coupon authority; destroying the machine-readable code;writing to a write once read many (WORM) memory; and, overwriting themachine-readable code.

In some embodiments of the method, the method also includes measuring alaser variable during the laser treatment. In some cases, the laservariable includes one or more of a duration of laser treatment, anelectrical energy delivered to the laser source during the lasertreatment, and a relative measure of laser energy generated by the lasersource during laser treatment.

In some embodiments of the method, the method also includes attaching aconsumable laser attachment to a hand piece prior to the lasertreatment. In some cases, the consumable laser attachment comprises themachine-readable code.

In one aspect, embodiments relate to a system for preventative lasertreatment. The system includes a code reader, a processor, and a lasertreatment system. The code reader is configured to read amachine-readable code. The processor is configured to verify themachine-readable code and prevent future verification of themachine-readable code. The laser treatment system includes a laserarrangement configured to generate a laser beam, an optical arrangementconfigured to direct the laser beam toward a dental hard tissue, and alaser controller configured to control a parameter of the laser beam inorder to heat at least a portion of a surface of the dental hard tissueto a temperature above 400° Celsius.

In some embodiments of the system, the optical arrangement includes oneor more of a beam delivery system, a hand piece, and a beam scanningsystem.

In some embodiments of the system, the optical arrangement includes ahand piece configured to attach to a consumable laser attachment. Insome cases, the consumable laser attachment includes themachine-readable code.

In some embodiments of the system, the machine-readable code includesone or more of a barcode, a two-dimensional (2D) barcode, a data matrix,a digital signature, a cryptocurrency, a magnetic strip, a transponderdevice, a microchip, and a radio-frequency identification (RFID) tag.

In some embodiments of the system, the processor is configured to verifythe machine-readable code by performing one or more of querying aledger; broadcasting to a ledger; decrypting the machine-readable code;recognizing a digest within the machine-readable code; querying a writeonce read many (WORM) memory; and, querying a coupon authority.

In some embodiments of the system, the processor is configured toprevent future verification of the machine-readable code by performingone or more of broadcasting to a ledger; submitting to a couponauthority; destroying the machine-readable code; writing to a write onceread many (WORM) memory; and, overwriting the machine-readable code.

In some embodiments of the system, the system includes a meterconfigured to measure a laser variable during treatment. In some cases,the laser variable includes one or more of a duration of lasertreatment, an electrical energy delivered to the laser source duringlaser treatment, and a relative measure of laser energy generated by thelaser source during laser treatment.

In one aspect, embodiments relate to a distribution system forpreventative dental laser treatment. The distribution system includes ahermetically sealed package, a single use dental fluoride treatment doselocated within the package, and a machine-readable code collocated withthe package. The machine-readable code is substantially inaccessible solong as the package remains intact. The machine-readable code, onceverified, is configured to allow use of a laser-based treatment system.

In some embodiments of the distribution system, the dental fluoridetreatment dose includes one or more of Sodium Fluoride, StannousFluoride, Titanium Fluoride, Acidulated-Phosphate Fluoride, and AmineFluoride.

In some embodiments of the distribution system, the dental fluoridetreatment dose includes one or more of a gel, a varnish, a paste, and afoam.

In some embodiments of the distribution system, the machine-readablecode includes one or more of a barcode, a two-dimensional (2D) barcode,a data matrix, a digital signature, a cryptocurrency, a magnetic strip,a transponder device, a microchip, and a radio-frequency identification(RFID) tag.

In some embodiments of the distribution system, the machine-readablecode includes one or more of a digital signature, a private key, apublic key, and a unique identifier; and the machine-readable code isassociated with data accessible to the dental laser system.

In some embodiments of the distribution system, the distribution systemincludes a consumable laser attachment. The consumable laser attachmentis configured to attach to a hand piece. The consumable laser attachmentincludes the machine-readable code. In some cases, the consumable laserattachment includes one or more of an authentication chip, a one-wirechip, and a radio-frequency identification (RFID) tag. In some cases,the consumable laser attachment is configured to be used intra-orally.In some cases, the consumable laser attachment is configured to direct alaser beam.

In some embodiments of the distribution system, the distribution systemalso includes a fluoride applicator. The fluoride applicator includesone or more of a tray, a brush, a swab, a needle, a syringe, and acloth.

In another aspect, some embodiments relate to one or more non-transitorycomputer-readable media storing instructions that are executable by aprocessing device. The execution of the instructions cause theprocessing device to read a machine-readable code; verify themachine-readable code; perform a laser treatment, based upon themachine-readable code; and, prevent future verification of themachine-readable code. In some cases, the laser treatment includesgenerating, using a laser arrangement, a laser beam; directing, using alaser arrangement, the laser beam toward a dental hard tissue; and,controlling, using a laser controller, a parameter of the laser beam inorder to heat at least a portion of a surface of the dental hard tissueto a temperature of at least 400° Celsius.

In another aspect, some embodiments relate to another distributionsystem for preventative dental laser treatment. The distribution systemincludes a hermetically sealed package, a machine-readable codecollocated with the package, and a consumable laser attachmentconfigured to attach to a hand piece located within the hermeticallysealed package. The machine-readable code is substantially inaccessibleso long as the package remains intact. The code, once verified, isconfigured to allow use of a laser-based treatment system. In somecases, the consumable laser attachment comprises the machine-readablecode.

In some embodiments of the distribution system, the dental fluoridetreatment dose includes one or more of Sodium Fluoride, StannousFluoride, Titanium Fluoride, Acidulated-Phosphate Fluoride, and AmineFluoride.

In some embodiments of the distribution system, the dental fluoridetreatment dose includes one or more of a gel, a varnish, a paste, and afoam.

In some embodiments of the distribution system, the machine-readablecode includes one or more of a barcode, a two-dimensional (2D) barcode,a data matrix, a two-dimensional (2D) barcode, a data matrix, a digitalsignature, a cryptocurrency, a magnetic strip, a transponder device, amicrochip, and a radio-frequency identification (RFID) tag.

In some embodiments of the distribution system, the machine-readablecode includes one or more of a digital signature, a private key, apublic key, and a unique identifier; and the machine-readable code isassociated with data accessible to the dental laser system.

In some embodiments of the distribution system, the consumable laserattachment includes the machine-readable code. In some cases, theconsumable laser attachment is configured to be used intra-orally. Insome cases, the consumable laser attachment is configured to direct alaser beam.

In some embodiments of the distribution system, the distribution systemalso includes a fluoride applicator. The fluoride applicator includesone or more of a tray, a brush, a swab, a needle, a syringe, and acloth.

In another aspect, some embodiments relate to another method forpreventative dental treatment. The method includes reading amachine-readable code; verifying, using a processor, themachine-readable code; performing a laser treatment, based upon themachine-readable code; and, preventing, using the processor, futureverification of the machine-readable code. The laser treatment includesgenerating, using a laser arrangement, a laser beam; directing, using anoptical arrangement, the laser beam toward a dental hard tissue; andcontrolling, using a laser controller, at least one parameter of thelaser beam in order to heat at least a portion of a surface of thedental hard tissue to a temperature no less than 400° Celsius.

Any combination and permutation of embodiments is envisioned. Otherobjects and features will become apparent from the following detaileddescription considered in conjunction with the accompanying drawings. Itis to be understood, however, that the drawings are designed as anillustration only and not as a definition of the limits of the presentdisclosure.

BRIEF DESCRIPTION OF DRAWINGS

Non-limiting and non-exhaustive embodiments of the invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 illustrates a laser system, in accordance with one embodiment;

FIG. 2A illustrates a transverse ring mode energy profile compared to aGaussian energy profile, in a certain exemplary embodiment;

FIG. 2B illustrates a transverse ring mode subtended upon a tiltedsurface, in an exemplary embodiment;

FIG. 2C illustrates relative energy absorption from the configurationshown in FIG. 2B with varying polarization arrangements, in an exemplaryembodiment;

FIG. 3 illustrates an optical arrangement for laser beam shaping, inaccordance with one embodiment;

FIG. 4 illustrates an analytically modeled temperature graph of enamelirradiated by a Gaussian beam, in accordance with one embodiment;

FIG. 5 illustrates an analytically modeled temperature graph of enamelirradiated by a first annular beam, in accordance with one embodiment;

FIG. 6 illustrates an analytically modeled temperature graph of enamelirradiated by a second annular beam, in accordance with one embodiment;

FIG. 7 illustrates an analytically modeled temperature graph of enamelirradiated by a super-Gaussian beam, in accordance with one embodiment;

FIG. 8 presents a flowchart of a method for preventative dental lasertreatment, in accordance with one embodiment;

FIG. 9 illustrates an exemplary system for preventative dental lasertreatment, in accordance with one embodiment;

FIG. 10 illustrates a preventative dental treatment system, inaccordance with one embodiment;

FIG. 11 illustrates a flowchart for a preventative dental treatmentmethod, in accordance with one embodiment;

FIG. 12 illustrates a contour temperature plot for irradiated dentalhard tissue, in accordance with one embodiment;

FIG. 13A illustrates internal reflection within an optic, in accordancewith one embodiment;

FIG. 13B illustrates a first technique for contact coupled irradiationof dental hard tissue, in accordance with one embodiment;

FIG. 13C illustrates a second technique for contact coupled irradiationof dental hard tissue, in accordance with one embodiment;

FIG. 14 illustrates a system for preventative inter-proximal dentaltreatment, in accordance with one embodiment;

FIG. 15 illustrates a system for cooling an optic contacting dental hardtissue, in accordance with one embodiment;

FIG. 16 illustrates a system for homogenizing a radiation, in accordancewith one embodiment;

FIG. 17A illustrates a package containing consumables for a preventativedental laser treatment, in accordance with one embodiment;

FIG. 17B illustrates an opened package containing consumables forpreventative dental laser treatment, in accordance with one embodiment;

FIG. 18A illustrates a system for performing a preventative dental lasertreatment, in accordance with one embodiment;

FIG. 18B illustrates a system for coupon verification, in accordancewith one embodiment;

FIG. 18C illustrates a block diagram of exemplary additional subsystemsof an exemplary dental laser system, in accordance with one embodiment;

FIG. 19A illustrates a flow chart representing a method for performing apreventative dental laser treatment, in accordance with one embodiment;

FIG. 19B illustrates a block diagram of a coupon issuance system, inaccordance with one embodiment;

FIG. 19C illustrates a block diagram of a coupon decryption system, inaccordance with one embodiment;

FIG. 19D represents a coupon authority system, in accordance with oneembodiment;

FIG. 20A illustrates a consumable dental laser attachment, in accordancewith one embodiment;

FIG. 20B illustrates a cross-sectional view of a consumable dental laserattachment, in accordance with one embodiment;

FIG. 21A illustrates a consumable dental laser attachment, in accordancewith one embodiment;

FIG. 21B illustrates a cross-sectional view a consumable dental laserattachment, in accordance with one embodiment;

FIG. 22 illustrates a block diagram of a system for authenticating alaser treatment coupon, in accordance with one embodiment;

FIG. 23 illustrates a flow diagram of a method for authenticating alaser treatment coupon, in accordance with one embodiment; and,

FIG. 24 illustrates a block diagram of a computer readable mediacomprising instructions performable by a processor, for authenticating alaser treatment coupon, in accordance with one embodiment.

DETAILED DESCRIPTION

Various embodiments are described more fully below with reference to theaccompanying drawings, which form a part hereof, and which show specificexemplary embodiments. However, the concepts of the present disclosuremay be implemented in many different forms and should not be construedas limited to the embodiments set forth herein; rather, theseembodiments are provided as part of a thorough and complete disclosure,to fully convey the scope of the concepts, techniques andimplementations of the present disclosure to those skilled in the art.Embodiments may be practiced as methods, systems or devices. Thefollowing detailed description is, therefore, not to be taken in alimiting sense.

Transverse Electromagnetic Modes for Even Treatment

As disclosed above, much research has been done on the use of a laserfor affecting an increase in acid resistance in dental hard tissue,however all of the existing research discloses using a laser having aGaussian energy profile output. Different wavelengths, energy levels,measurement and control techniques have been explored, but to date thereis no solution described in the literature that uses an alternativelaser energy profile.

Use of a Gaussian energy profiles (or near-Gaussian energy profiles likethose produced by slab CO₂ lasers which are Gaussian in one axis andunstable in a second axis) limit performance of laser treatment. Forexample, see “Nondestructive Assessment of the Inhibition of EnamelDemineralization by CO2 Laser Treatment Using Polarization SensitiveOptical Coherence Tomography,” by Hsu et al., published in J. BiomedOptics in 2008 and incorporated herein by reference. Hsu et al. showthat melting of the enamel is easily achieved (see FIG. 3 a , whichshows melted enamel) and a Gaussian energy profile causes variabletreatment effectiveness over a focal region of the laser beam (see FIG.3 b , which shows uneven melting of enamel). Consistently effectivelaser treatment requires that surface temperatures of a toothexperiencing laser heating are held very precisely. However, use of aGaussian energy profile introduces uneven heating of dental tissue byits very nature. An energy dense peak, at a center of a Gaussian beamwill introduce peak heating at the tissue surface. And, a low energycircumference of the laser beam (encompassing the “wings” or “tails” ofthe Gaussian energy profile) will result in, relatively speaking, muchless heating of the tissue. For this reason, there is effectively no wayto eliminate variable heating of the tissue with a laser beam having aGaussian laser energy profile. Laser systems for delivering non-Gaussianenergy profiles specifically for the even heating of dental hard tissueare therefore sought.

Further complicating consistent and even heating of dental hard tissuewith a laser is that an energy density of a laser beam variessubstantially at locations away from the focal region. Energy density ofthe laser beam varies based upon distance away from the focal region ata rate that depends on a rate of convergence (e.g., numerical aperture[NA]) of the laser beam. A highest energy density occurs at the focalregion. Typically, the focal region is located a prescribed distance(e.g., focal length) away from the focus optic, which is in a system(commonly within a hand piece). A distance between the hand piece andthe dental surface being treated, therefore, must be carefullymaintained in order to control the energy density of the beam as itaffects the surface. Additionally, a density of energy absorbed into thedental surface varies depending on an angle of an optical axis relativethe dental surface (more energy is absorbed by the dental surface atmore orthogonal angles). A commercially viable hand piece ultimatelymust be used by a dental practitioner in a real-world clinic. So,precise placement of the focal region coincident and parallel with thesurface of the dental tissue being treated cannot reasonably be expectedin situ. Instead, carefully specifying a laser beam having an energyprofile and a rate of convergence that is insensitive to smalldeviations from the focal region is preferred. Exemplary embodiments aredisclosed herein that address these above-mentioned problems.

FIG. 1 illustrates a preventative dental laser system 100 in accordancewith one embodiment. The preventative dental laser system 100 delivers alaser beam 110 to a dental hard tissue 112 (e.g., enamel, dentin, orcementum). The laser beam is generated by a laser source 114. Anexemplary laser source 114 is a carbon dioxide (CO₂) laser, for exampleHPP DL-500 from Access Laser of Everett, Wash., U.S.A. Typically, thelaser source is selected to generate a laser beam 110 that is wellabsorbed (e.g., has a wavelength having an absorption coefficientgreater than 1 cm⁻¹, 100 cm⁻¹, or 1,000 cm⁻¹) by the dental hard tissue112. The laser beam has a transverse electromagnetic mode (TEM) that isnon-Gaussian. For example, in accordance with one embodiment, the laserbeam 110 has a TEM that comprises at least one ring (e.g., TEM 01*).According to some embodiments, the system 100 comprises a beam shaper116. The beam shaper 116 in some embodiments introduces the transversering mode to the laser beam 110. Exemplary beam shapers 116 forintroducing a transverse ring mode to the laser beam can include: one ormore of axicons 118A-B, an aperture (e.g., annular slit located at aback focal plane of a convergent lens), a spatial light modulator, fiberoptics or waveguides, a tunable acoustic gradient (TAG) lens, adiffractive optical element (DOE), spiral phase plates (SPP), opticalphase plates, a rod homogenizer, and spatial phase masks. Alternatively,in some embodiments, the laser beam 110 is generated having anon-Gaussian (e.g., transverse ring) mode. Exemplary laser sources 114that can produce a laser beam 110 having a non-Gaussian (e.g.,transverse ring) mode are DC series CO₂ lasers from ROFIN-SINAR LaserGmbH of Hamburg, Germany. The laser beam 110 is focused by a focus optic120 to a focal region 122. An exemplary focus optic is (Thorlabs PN:LA7728-G) a 1″ diameters ZnSe plano-convex lens, with a focal length of200.0 mm having an antireflective coating in a range from 7 to 12 μm. Insome embodiments, the laser beam 110 at the focal region 122 maintainsits non-Gaussian (e.g., transverse ring) energy profile. The focallength of the focus optic, in some embodiments, can be specified inorder to control rate of convergence (and/or divergence) of the laserbeam. A reduced rate of convergence (i.e., slower optical system)reduces changes in energy profile away from the focal region. Forexample, a collimated laser beam having a diameter of 10 mm acted uponby a focus optic having a 200 mm focal length converges at a numericalaperture (NA) of 0.025. Comparatively, the same 10 mm laser beam beingfocus by a 50 mm focal length focus optic will converge at a NA of 0.1.Beam widths are shown for a 0.025 NA beam and a 0.1 NA at certaindistances away from focus in the table below:

Numerical Aperture (NA) 0.025 0.1 (-) Wavelength 10.6 (micron) FocalRegion Width 135.0 33.7 (micron) Rayleigh Length 5.4 0.3 (mm) Width ofBeam 0.1mm from Focal 135.0 35.2 Region (micron) Change in Area (orEnergy Density) 0.0% 8.8% 0.1 mm from Focal Region (%) Width of Beam 1mmfrom Focal Region 137.3 105.5 (micron) Change in Area (or EnergyDensity) 3.4% 878.4% 1mm from Focal Region (%) Width of Beam 10 mm fromFocal 284.1 1000.6 Region (micron) Change in Area (or Energy Density)343.1% 87839.1% 10 mm from Focal Region (%)

As is manifest in the table above, a smaller numerical aperture (e.g.,less than 0.1) allows small deviations from the focal region (e.g.,+/−0.5, 1, 2, 3, or 5 mm) to have relatively small differences in energydensity (e.g., 10%, 25%, or 50%). Use of the system typically includes aclinician placing a hand piece within a patient's mouth and directingthe laser beam toward a dental hard tissue surface. The location of thefocal region relative the surface is therefore affected by an opticalpath length (between the focus optic and the surface). The optical pathlength must be controlled by the clinician. Accurate control of adistance between the hand piece and the dental hard tissue isimpractical in situ. For this reason, selection of focal length (ornumerical aperture [NA]) in some embodiments is made to provide apseudo-invariable energy density near the focal region (for example,less than a 10% change in energy density [e.g., fluence] in 1 mm fromfocus). In accordance with one embodiment, the non-Gaussian mode isimparted upon the laser beam 110 by a beam shaper comprising one or moreaxicons 118A-118B. As shown in FIG. 1 , a first axicon in someembodiments is used to form a quasi-Bessel beam 124 and then a divergingtransverse ring beam 126. In some embodiments, the diverging ring beam126 is focused directly by the focus optic 122. Alternatively, a secondaxicon 118B having a wedge angle substantially equal to that of thefirst axicon 118A is used to collimate the diverging ring beam 126 intoa collimated laser beam 110 having a transverse ring mode. In someembodiments, a mask 128 is used to partially occlude the laser beam 110,in order to ensure that a center portion of the laser beam 110 issubstantially free from laser energy.

According to one embodiment, the system additionally includes a beamscanning system. Exemplary beam scanning systems include Risley prisms,spinning polygon mirrors, voice coil scanners (e.g., Part No. MR-15-30from Optotune of Dietikon, Switzerland), galvanometers (e.g., LightningII 2-axis scan head from Cambridge Technology of Bedford, Mass.,U.S.A.), and a gantry with a translating focus optic. Scanning methodsrelated to dental laser systems are described in U.S. Pat. No. 9,408,673by N. Monty et al., incorporated herein by reference.

According to one embodiment, a polarization of the laser beam 110 iscontrolled. In some cases, an intra-cavity polarization generator isused (not shown) (e.g., a leaky-mode polarizing grating mirror at anoutput coupler of a waveguide CO₂ laser). Alternatively, in other casesan external polarization converter 130 is used to convert the laser beamto a desired polarization state. Exemplary polarization converters 130include one half waveplate, one quarter waveplate, and a linear toradial/tangential polarization converter that is composed of 8 low-orderhalf-wave segments and which has a fixed and well-defined fast-axisorientation. The laser beam 110 in certain exemplary embodiments has acylindrical polarization (i.e., axially symmetric polarization) (e.g.,radial or tangential). Alternatively, in other certain exemplaryembodiments, the laser beam 110 has a polarization that is linear,circular, random, or azimuthal. Polarization of the laser beam in someembodiments affects the amount of energy delivered into the dental hardtissue.

An amount of reflection (e.g., reflectivity) of a radiation at a surfaceof a material is related to polarization. In some situations, it isappropriate to understand a relationship between polarization andreflectivity according to Fresnel equations. Reflectivity of ans-polarized light is described by a first Fresnel equation as:

$R_{s} = {❘\frac{{n_{1}\cos\theta_{i}} - {n_{2}\sqrt{1 - \left( {\frac{n_{1}}{n_{2}}\sin\theta_{i}} \right)}}}{{n_{1}\cos\theta_{i}} + {n_{2}\sqrt{1 - \left( {\frac{n_{1}}{n_{2}}\sin\theta_{i}} \right)}}}❘}^{2}$

where R_(s), is reflectivity for s-polarization, n₁ is index ofrefraction of a first medium (e.g., air), n₂ is an index of refractionof a second medium (e.g., dental hard tissue), θ_(i) is an angle ofincidence the radiation is reflected from the surface about.Reflectivity for p-polarization, R_(p), is described by a second Fresnelequation as:

$R_{p} = {❘\frac{{n_{1}\sqrt{1 - \left( {\frac{n_{1}}{n_{2}}\sin\theta_{i}} \right)}} - {n_{2}\cos\theta_{i}}}{{n_{1}\sqrt{1 - \left( {\frac{n_{1}}{n_{2}}\sin\theta_{i}} \right)}} + {n_{2}\cos\theta_{i}}}❘}^{2}$

Finally, energy transmitted into the material is all of the energy notreflected as described byT _(s)=1−R _(s)and,T _(p)=1−T _(p)where T_(s) is s-polarized radiation transmitted into the material; and,T_(p) is p-polarized radiation transmitted into the material.

Polarization of laser radiation is known to affect industrial laserapplications, such as laser welding. In “Effects of Radial andTangential Polarization in Laser Material Processing” by R. Weber etal., published in Physics Procedia in 2011, incorporated herein byreference, an overview is given on polarization control and polarizationeffects as they relate to state-of-the-art industrial laser processingactivities, including laser cutting, laser welding, and laser annealing.FIGS. 2A-C illustrates an example showing how polarization effectstransmission from R. Weber et al. FIG. 2A is an energy profile graph 210having normalized intensity in normalized units along a first verticalaxis 212 and radial position in micron along a first horizontal axis214. A transverse ring mode 216 is compared with a Gaussian mode 218within the graph. Referring now to FIG. 2B, a laser beam 220 is shownirradiating a surface 222. The surface is not normal to the laser beam220, but instead is tilted at 80° relative the laser beam 220. Absorbedenergy resulting from the configuration shown in FIG. 2B is illustratedin FIG. 2C. A first image 230 of the surface 222 illustrates absorbedenergy when the laser beam 220 is circularly polarized. A second image232 image of the surface 222 illustrates absorbed energy when the laserbeam is radially polarized. A third image 234 of the surface illustratesabsorbed energy when the laser beam is tangentially polarized. In theconfiguration described with reference to FIG. 2B, absorption of energyis more constant over the entire area irradiated by the laser beam withcircular polarization 230. The phenomenon described in reference toFIGS. 2A-C can be understood mathematically using the Fresnel equationsdescribed above.

Other forms of beam shaping have been identified that produce energyprofiles that are constant (e.g., top hat or flat-top) or near-constant(super-Gaussian). Flat-top (i.e., top hat) laser energy profiles are notdefined as free space modes, as the energy profile changes as the beampropagates. Flat-top energy profiles can be shaped by diffractiveoptical elements (DOE), for example PN: ST-273-A-Y-A from Holo/OR ofNess Ziona, Israel. Other DOEs can be used to produce a diffuse orhomogenized laser beam. Generally, all of these DOEs only produce aflat-top energy profile at focus (e.g., beam waist) and outside of focusthe energy profile is indeterminate. For this reason, flat-top andtop-hat energy profiles (which would theoretically be ideal for thedescribed application) in practice are difficult to implement.Specifically, the flat-top energy profile must be configured so itsposition along the optical axis coincides with the surface of the tooth.Away from the flat-top profile position (e.g., focus) along the opticalaxis, the flat-top profile changes and exhibits “hot spots” (or areas ofpeak energy density). These “hot spots” when positioned at the surfaceof the tooth typically cause unwanted thermal damage to the tooth (e.g.,melting, cracking, and ablation). In order to prevent this with aflat-top energy profile, the optical path length to the surface of thetooth must remain constant during treatment. This is difficult inpractice, as every treatment surface of each tooth within the mouth mustbe irradiated at a clinically viable speed (e.g., a total treatment timeof less than 30 minutes) and because of the complex nature of workingwithin an oral cavity. Like the flat-top energy profile a super-Gaussianenergy profile changes with propagation distance. However, unlike theflat-top energy profile the changes are slow and predictable. Forexample, short distances (e.g., +/−1 mm or +/−10 mm) away from thesuper-Gaussian energy profile location (e.g., focus) the energy profileshape changes only slightly. Typically, changes away from thesuper-Gaussian energy profile are toward a shape that is more Gaussianor more donut (i.e., dog ears) in its energy profile. This is againunlike the flat-top energy profiles described above that can introducepeak fluence “hot spots” in indeterminate locations during propagation.In some embodiments, a transverse energy profile of the laser beam 110is not a ring mode, but instead has a more constant energy distribution,for example a super-Gaussian.

A standard Gaussian laser beam energy (or power) profile at focus can bemodeled according to:

$I_{(r)} = {I_{0}e^{{- 2}{(\frac{r}{\omega_{0}})}^{2}}}$where, I_((r)) is a transverse energy (or power) density profile, I₀ isa peak energy (or power) density value (which is typically located at acenter of the beam), r is a dependent variable for radius or distanceaway from the center of the beam, and ω₀ is a 1/e² half width of thelaser beam. A higher-order Gaussian (e.g., super-Gaussian) laser beamenergy (or power) profile at focus can be modeled according to:

$I_{(r)} = {I_{0}e^{{- 2}{(\frac{r}{\omega_{0}})}^{n}}}$where, n is an order of the super-Gaussian, for example 4, 6, 8, etc. Inaccordance with one embodiment, the system comprises a laser sourceconfigured to generate a laser beam having a super-Gaussian beamprofile.

In some embodiments, a phase-graded mirror is employed within a laserresonator to generate the laser beam having a super-Gaussian beamprofile. For example, researchers have shown that generation of asuper-Gaussian beam using a phase-grated mirror can increase energyextraction within a carbon dioxide laser. “Super-Gaussian Output from aCO₂ Laser by using a Graded-Phase Mirror,” by P. Belanger et al.,published in Optics Letters in 1992, incorporated herein by reference,teaches formation of super-Gaussian output resonators with orders of 4and 6 in a transverse excited atmospheric pressure (TEA) CO₂ laser.Later in 1998, G. Bourdet et al. taught that a slab CO₂ couldtheoretically experience increased energy extraction from the gainmedium by using a graded-phase mirror to generate a quasi-super-Gaussianlaser mode in “Theoretical investigations of a slab CO₂ Laser Resonatorwith Graded-Phase Mirror,” published in Optics Communications andincorporated herein by reference.

In some embodiments, active optical elements are used to generate orshape a mode of the laser beam. For example, T. Cherezova et al.reported formation of super-Gaussian modes having orders of 4, 6, and 8using a deformable mirror in a carbon dioxide laser resonator in 2001 ina paper entitled “Active laser resonator performance; formation of aspecified intensity output,” published in Applied Optics andincorporated herein by reference.

According to a certain embodiment illustrated in FIG. 3 , an opticalarrangement 300 is used to shape a laser beam 310 into an energy profilehaving a more uniform energy distribution. A collimated laser beam 312having a substantially Gaussian profile 313 is converged to a waistproximal a first axicon 314. The waist of the converging laser beam isgenerally centered on the first axicon 314. Down beam from the firstaxicon 314, the laser beam passes through a Bessel beam region 316 thena diverging annulus ring region 318. A second axicon 320 is located downbeam from the first axicon a specified distance along an optical axis,such that the diverging annulus ring is of a certain annulus diameter,where the laser beam is incident the second axicon 320. The secondaxicon 320 then corrects (e.g., collimates) the diverging ring mode intoa ring mode that has a substantially constant diameter (D) as itpropagates. The ring mode has an annular Gaussian energy profile 321over the annulus. However, because the waist of the converging beam waslocated near the first axicon 314, the laser beam was diverging as itwas acted on by the first axicon 314 as well as the second axicon 320.As a result, an annulus width (w) of the ring mode continues to divergeas the laser beam propagates. A focus optic is located a predetermineddistance down beam from the second axicon 320, such that at the locationof the focus optic the diameter (D) of the annulus is generally equal tothe width (w) of the annulus. Here, because of the partially overlappingannular energy profiles, the laser beam has a more constant energyprofile 323. Finally, the focus optic 322 converges the laser beam to afocal region. Alternatively, in some certain embodiments, a moreconstant energy profile (e.g., super-Gaussian) is formed by anintra-cavity spatial filter or a spatial filter external to a lasercavity.

To understand and demonstrate effects of energy profile on heating ofdental enamel a mathematical model is disclosed. The mathematical modelassumes Beers radiation absorption, Newtonian convection, and Fourierconduction. The model was coded using a nodal finite element analysis,which is described by J. Van de Ven et al. in “Laser TransmissionWelding of Thermoplastics—Part I: Temperature and Pressure Modeling”published in J. Manuf. Sci. Eng. In October of 2007 and incorporatedherein by reference. For the model, a 9.3 μm wavelength radiation isassumed to have a reflectivity of 0.4 and an absorption coefficient of0.5 μm⁻¹ in dental enamel. An optical pulse of 1000 is also assumedhaving an instantaneous rise and fall time. Temperature within theenamel immediately after the laser pulse is found from the model.

A first temperature plot 410 is illustrated in FIG. 4 . The firsttemperature plot shows depth into the enamel in micron along a firstvertical axis 412 and width of the laser beam 110 in micron along afirst horizontal axis 414. Temperature is grayscale coded in degreesCentigrade according to a color bar 416. The laser beam 110 for thefirst temperature plot comprises a purely Gaussian energy profile with a1/e² beam diameter of 0.25 mm.

A second temperature plot 510 is illustrated in FIG. 5 . The secondtemperature plot 510 shows depth into the enamel in micron along asecond vertical axis 512 and width of the laser beam 510 in micron alonga second horizontal axis 414. Temperature is grayscale coded in degreesCentigrade according to a color bar 516. The laser beam 110 for thesecond temperature plot comprises a transverse ring mode with a Gaussianannular energy profile having a 1/e² beam width of 0.125 mm and annulardiameter of 0.175 mm.

A third temperature plot 610 is illustrated in FIG. 6 . The thirdtemperature plot 610 shows depth into the enamel in micron along a thirdvertical axis 612 and width of the laser beam 610 in micron along athird horizontal axis 614. Temperature is grayscale coded in degreesCentigrade according to a color bar 616. The laser beam 110 for thethird temperature plot comprises a transverse ring mode with a Gaussianannular energy profile having a 1/e² beam width of 0.125 mm and annulardiameter of 0.125 mm. Review of FIGS. 4-6 , shows that a greater area oftissue is heated to a constant temperature with transverse ring modelaser irradiation.

A fourth temperature plot 710 is illustrated in FIG. 7 . The fourthtemperature plot 710 shows depth into the enamel in micron along afourth vertical axis 712 and width of the laser beam 710 in micron alonga fourth horizontal axis 614. Temperature is grayscale coded in degreesCentigrade according to a color bar 716. The laser beam 110 for thefourth temperature plot comprises a super-Gaussian energy profile withan order of 4 and a beam width of 0.125 mm. Review of FIGS. 4-7 , showsthat a greater area of tissue is heated to a constant temperature with anon-Gaussian (i.e., super-Gaussian and transverse ring) mode laserirradiation.

FIG. 8 presents a flowchart of a method 800 for preventative dentallaser treatment in accordance with one embodiment. A laser sourcegenerates a laser beam having a non-Gaussian energy profile (e.g., atransverse ring mode) 810. In some cases, the laser source firstgenerates the laser beam and then an energy profile of the laser beam isconverted into a non-Gaussian energy profile. In other cases, the lasersources generates the laser beam having a non-Gaussian energy profilenatively. In accordance with one embodiment, the non-Gaussian energyprofile comprises a transverse ring mode. Examples of transverse ringmodes include TEM 01* modes, Laguerre-Gaussian modes, Hermite-Gaussianmodes, Bessel, and Bessel-Gaussian modes. In some embodiments, thenon-Gaussian energy profile is used to produce a constant ornear-constant energy profile (e.g., super-Gaussian) somewhere along thepropagation of the laser beam (e.g., a focal region). Next, the laserbeam is converged to a focal region 812, typically using a focus optic.The focal region is located near a surface of dental hard tissue (e.g.,tooth enamel). Finally, at least one parameter of the laser beam iscontrolled 814 to deliver a controlled irradiation and evenly heat aportion of the surface of the dental hard tissue to within a range ofbetween about 400° C. and about 1300° C. Examples of laser parametersinclude: repetition rate, pulse duration, pulse energy, focal regionposition, laser scan speed, focal region width, wavelength, etc.

To aid in practice of the claimed invention and parameter selection atable is provided below with exemplary ranges and nominal values forrelevant parameters.

Parameter Min. Max. Nom. Repetition Rate 1 Hz 10 KHz 1 KHz Pulse Energy1 μJ 1 J 10 mJ Focal Region 1 μm 10 mm 1 mm Width Fluence 0.01 J/cm² 1MJ/cm² 1J/cm² Wavelength 200-500 nm 4000-12000 nm 10.6 μm Numerical0.00001 0.5 0.01 Aperture (NA) Focal length 10 mm 1000 mm 200 mm AveragePower 1 mW 100 W 1 W Peak Power 50 mW 5000 W 500 W Scan Speed 0.001 mm/S100,000 mm/S 10 mm/S ScanLocation 0 10x Focal Region 0.5x Focal RegionSpacing Width Width Polarization Linear, circular, random, cylindrical,radial, tangential Mode/Energy Super-Gaussian, annular ring mode,Profile TEM 01*, flat-top, Laguerre-Gaussian, Hermite-Gaussian, Bessel,Bessel-Gaussian

An exemplary system 900 is shown in FIG. 9 . The system 900 includes aconsole 910. The console 910 houses components of the system 900, forexample, a laser source to generate the laser beam, a direct current(DC) power supply to power the laser source, a beam shaper to shape anenergy profile of the laser beam, a compressed air system to delivercompressed air for bulk cooling of dental hard tissue being treated, anda user interface 912 for user control. A beam delivery system 914directs the laser beam to a hand piece 916. Exemplary beam deliverysystems 914 include articulated arms, waveguides, and fiber optics. Anexemplary articulated arm is provided by Laser Mechanisms of Novi,Mich., U.S.A. The hand piece 916 is configured to be used intra-orally(i.e., within an oral cavity). Typically, the hand piece 916 includes afocus optic (not shown) that converges the laser beam to a focal regionoutside of the hand piece 916. In accordance with one embodiment, thesystem 900 is operated with a foot pedal 918, which is configured toinitiate the laser source.

In accordance with one embodiment, the system 900 is used by aclinician. First, the clinician inputs operating parameters into theuser interface 912, for example by using a touch screen. Then theclinician places the hand piece 916 within a patient's mouth and directsthe hand piece 916 toward dental hard tissue. For example, the clinicianpositions the hand piece 916 so that a focal region of the laser beam iscoincident with or near (e.g., +/−1 mm, 2 mm, 3 mm, or 5 mm) a surfaceof a tooth. Then, the clinician activates the laser by stepping on afoot pedal 918. The clinician moves the hand piece 916 within thepatient's mouth, carefully directing the focal region of the laser beamnear every treatment surface of the patient's teeth.

Contact Coupled Laser Delivery

FIG. 10 illustrates a preventative dental treatment system 1000 inaccordance with one embodiment. The preventative dental treatment system1000 delivers a radiation (e.g., laser beam) 1010 to a dental hardtissue 1012 (e.g., enamel, dentin, or cementum). The radiation isgenerated by a radiation source (e.g., laser source) 1014. An exemplarylaser source 1014 is a carbon dioxide (CO₂) laser, for example HPPDL-500 from Access Laser of Everett, Wash., U.S.A. Typically, theradiation source is selected to generate a radiation 1010 having awavelength that is well absorbed (e.g., has an absorption coefficientgreater than 1 cm⁻¹, 100 cm⁻¹, or 1,000 cm⁻¹) by the dental hard tissue112. Exemplary wavelengths include wavelengths in either of a firstrange between 200 and 500 nm and second range between 4 and 12 μm. Theradiation 1010 is delivered to a hand piece 1016 using a radiationdelivery system 1018. Exemplary radiation delivery systems includearticulating arms, fiber optics, and hollow wave guides. Certainexemplary articulating arms are provided by Laser Mechanisms of Novi,Mich., U.S.A. The hand piece 1016 is configured to be used intra-orally(i.e., within an oral cavity). The hand piece comprises a coupling optic1020. The coupling optic 1020 accepts the radiation 1010 at a first endof the coupling optic. The radiation 1010 is transmitted within thecoupling optic 1020. According to one embodiment, the radiation 1010 isultimately ejected from a second end of the coupling optic. Exemplarycoupling optics include waveguides, fiber optics, rods, and prisms. As,the radiation propagates within the coupling optic 1020 it is internallyreflected at interfaces (e.g., sides) of the coupling optic 1020 and itssurroundings. Commonly, air surrounds the coupling optic 1020. Thecoupling optic in some embodiments comprises one of diamond, quartz(i.e., fused silica), glass, sapphire, zinc selenide, or zinc sulfide.In one embodiment the coupling optic 1020 is made out of diamond andproduced by chemical vapor deposition (CVD). CVD diamond has an index ofrefraction of 2.38 at a wavelength of 10.6 μm. Index of refraction ofair at a wavelength of 10.6 μm is 1.0. Because, air has a much lowerindex of refraction than CVD diamond the radiation 1010, in general,experiences total internal reflection (TIR) at optic-air interfaces asit propagates within the coupling optic. The coupling optic 1020 ispositioned within the hand piece 116, so that a surface of the couplingoptic is exposed. During use of the system 1000, the coupling optic 1020is placed in contact with dental hard tissue 1012. Depending onradiation parameters (e.g., wavelength), coupling optic parameters(e.g., material [index of refraction]), and optical path parameters(e.g., entrance angle), a varying portion of the radiation 1010 istransmitted into the dental hard tissue 1012 at a point of contactbetween the coupling optic and the dental hard tissue 1012.

Optionally, after exiting out of the second end of the coupling optic1020 radiation not delivered to the dental hard tissue 1012 is analyzedby a detector 1022. Exemplary detectors include photodiodes,spectrometers, spectrophotometers, photodetectors, pyroelectricdetectors, and thermopiles. In some certain embodiments, the detector1022 is used to determine an energy or power amount of the radiation1010 not transmitted into the dental hard tissue. This measurement canindicate whether or not effective treatment is being performed bydetermining if in fact energy is being delivered into the dental hardtissue 1012. If a small portion of total radiation energy (e.g., lessthan or equal to 50% of total radiation energy) is detected, than aninference can be made that radiation energy is being delivered to thedental hard tissue 1012 and treatment is being effectively performed.Alternatively, if a large portion (e.g., greater than 50% of the totalradiation energy) is detected, than an inference can be made thatradiation energy is not effectively being delivered to the dental hardtissue 1012 and that treatment is not effectively being performed.

A certain exemplary method for use of the system 1000 is described withreference to a flowchart 1100 in FIG. 11 . First, a radiation (e.g.,laser beam) is generated 1110. Typically, the radiation is generatedwith a radiation source (e.g., laser source). Exemplary laser sourcesinclude carbon dioxide (CO₂) lasers, carbon monoxide (CO) lasers,excimer lasers, fiber lasers, diode pumped solid state (DPSS) lasers,and semiconductor lasers. The radiation is controlled 1112. Typically,one or more parameters of the radiation are controlled with acontroller. Exemplary controllers include laser control boards (e.g.,Maestro from LANMark Controls Inc. of Acton, Mass., U.S.A.). Theradiation is delivered along an optical path and coupled into an optic.Then, the radiation is internally reflected within the optic 1114. Insome certain exemplary embodiments, the radiation while transmittingthroughout the optic experiences total internal reflection (TIR). Adental hard tissue is then contacted with the optic 1116. For example, aside of the optic along which the radiation experiences internalreflection is placed in direct contact with a dental hard tissue (e.g.,enamel or dentin). Finally, a portion of the radiation is coupled intothe dental hard tissue 1118 at a point of contact between the optic andthe dental hard tissue. In certain exemplary embodiments, the radiationis coupled into the dental hard tissue by at least one of frustratedtotal internal reflection (FTIR), attenuated total internal reflection(ATIR), and an evanescent wave.

To aid in practice of the claimed invention and parameter selection atable is provided below with exemplary ranges and nominal values forrelevant parameters.

Parameter Min. Max. Nom. Repetition Rate 1 Hz 100 KHz 1 KHz Pulse Energy1 μJ 10 J 10 mJ Focal Region Width 1 μm 10 mm 1 mm Fluence 0.01J/cm²IMJ/cm² U/cm² Wavelength 200-500 nm 4000-12000 nm 10.6 μm Average Power1 mW 100 W 1 W Peak Power 50 mW 5000 W 500 W CouplingOptic 0.1 mm 50 mm5 mm Width Optic Materials Sapphire, Quartz, Diamond, UV Fused Silica,Zinc Selenide, Zinc Sulfide, Magnesium Fluoride, Barium Fluoride,Calcium Fluoride, Germanium, and Silicon.

Further description is provided below by way of certain exemplaryembodiments. According to some embodiments, an ultraviolet (UV) lasersource is used to produce a UV laser beam for treatment. Exemplary UVlaser sources include diode pumped solid state (DPSS) lasers, frequencyquadrupled Nd:YAG lasers, excimer lasers, and fiber lasers. An exemplaryfiber laser series is ULM/ULR-355 Series from IPG Photonics of Oxford,Mass., U.S.A. The ULM/ULR-355 Series offers a 200 W average power systemthat operates in a quasi-continuous wave (CW) mode with a wavelength of355 nm, a pulse duration of 1.4 nS, and repetition rate settings of 20,40, and 80 MHz. Hydroxyapatite (HAP) has a relatively high absorption at355 nm. The absorption coefficient of HAP at 355 nm is approximately 0.1μm⁻¹ (i.e., 1000 cm⁻¹). To understand the potential for a UV lasersource (e.g., ULM/ULR-355) a mathematical model is disclosed. Themathematical model assumes Beers absorption, Newtonian convection, andFourier conduction. The model was coded using a nodal finite elementanalysis, which is described by J. Van de Ven et al. in “LaserTransmission Welding of Thermoplastics—Part I: Temperature and PressureModeling,” published in J. Manuf. Sci. Eng. in October of 2007 andincorporated herein by reference. The model was run assuming a 200 Wirradiative power, 40% reflectivity between the air and enamel surface,0.1 μm⁻¹ absorption coefficient, and a 1 mm 1/e² laser beam diameter atthe enamel surface with a Gaussian profile. The modeled temperature risefor the above conditions is illustrated in the contour line plot 1200 inFIG. 12 .

Referring to FIG. 12 , the contour line plot 1200 shows depth into theenamel in μm along a first vertical axis 1212 and radial distance awayfrom a center of the laser beam in μm along a first horizontal axis1214. Temperature in degrees Celsius is grayscale coded according to thecolor bar 1216. The contour plot 1210 illustrates only half of a totalwidth of the area of enamel affected by the laser beam. Said another waya center of the laser beam at a surface of the enamel is shown in FIG.12 at location (0, 0). Peak surface temperature occurs at the center ofthe laser beam and at the surface and is modeled to be 974° C. It can beseen in FIG. 12 that temperature rise within the enamel occurs even tensof micron deep (e.g., 20 μm). This is because enamel absorbs UVradiation well, but not as highly as it absorbs mid-infrared irradiation(e.g., 9-11 μm wavelengths). For example, optical penetration depth(depth within which ˜63% of irradiation is absorbed) for ultraviolet(UV) radiation is approximately 100 μm; and, optical penetration depthfor 9.3 μm wavelength radiation is approximately 2 μm. In some cases,increased optical penetration depth is an advantage for treatment,because the tissue is treated less superficially. A disadvantage ofincreased optical penetration depth is that a greater volume of enamelmust be irradiated to treat the same area of the tooth; and as a result,more energy must be delivered to raise the temperature of the greatervolume of enamel. Returning to the example above, a 200 W powered laserpulse and 100 μS pulse duration will deliver 20 mJ of pulse energy tothe tooth. Finally, the laser can be pulsed at a repetition rate.Exemplary repetition rates include rates less than or equal to 100 Hz(e.g., 50 Hz). With a 20 mJ laser pulse energy and a repetition rate of50 Hz, 1 W of laser power is delivered on average to the tooth. About 1W of bulk heating power can be removed from a tooth by way of forcedconvection (e.g., blowing air or another fluid). An additional benefitof treatment with a UV radiation is from tooth whitening resulting fromphotobleaching. J. Schoenly et al. describe removal of extrinsic stainsusing a 400 nm wavelength laser in “Near-UV Laser Treatment of ExtrinsicDental Enamel Stains,” published in Lasers Surg Med. in March of 2012,incorporated herein by reference. The above example modeled a Gaussianbeam being delivered to a dental hard tissue in order to demonstratefeasibility of a UV laser beam for acid dissolution inhibitiontreatment. In certain exemplary embodiments, the UV laser beam isdelivered by way of an optic that contacts the dental hard tissue.

Referring to FIGS. 13A-C, in some embodiments, an optic (e.g.,waveguide) 1310 contacts a dental hard tissue in order to transmitradiation 1312. FIG. 13A schematically illustrates a radiation 1312propagating through the optic 1310. A medium 1314 surrounding the optic1310 in FIG. 13A is air. Air has an index of refraction of one (1.0);and, the optic typically has an index of refraction greater than one.Generally speaking, because the surrounding medium 1314 has a lowerindex of refraction than that of the optic 1310, the radiation 1312experiences internal reflection (e.g., total internal reflection [TIR])within the optic 1310.

FIG. 13B schematically represents a first technique for contact couplingradiation 1312 into dental hard tissue 1316. In the first technique, theoptic 1310 has an index of refraction that is greater than the index ofrefraction of the dental hard tissue. For example, in some exemplaryembodiments a high index optic material is used (e.g., diamond [n=2.38],ZnSe [n=2.61], or ZnS [n=2.37]) and index of refraction for dentalenamel is about 1.6. In this case, radiation 1312 reflected at aninterface between the optic 1310 and the dental hard tissue 1316experiences attenuated internal reflection (e.g., attenuated totalinternal reflection [ATIR]). An evanescent wave 1318 (i.e., evanescentfield) comprising a portion of the radiation is formed, which penetratesthe dental hard tissue 1316. The evanescent wave 1318 penetrates acertain depth 1320 into the dental hard tissue. The depth 1320 of theevanescent wave 1318 penetration can be approximated using arelationship:

$d = \frac{\lambda_{0}}{2\pi\sqrt{{n_{1}^{2}\sin\theta^{2}} - n_{2}^{2}}}$where, d is penetration depth 1320 of the evanescent wave 1318; λ₀ isvacuum wavelength of the radiation 1312; n₁ is index of refraction ofoptic 1310; n₂ is index of refraction of material surrounding the optic(e.g., the dental hard tissue 1316 or the air 1314); and, θ is an angleof incidence 1322 of the radiation 1312 at the interface. Underconditions of total internal reflection (TIR), the angle of incidence1322 has a value which is greater than a critical angle. The criticalangle can be approximated by using a relationship:

$\theta_{critical} = {\sin^{- 1}\frac{n_{2}}{n_{1}}}$where, θ_(critical) is the critical angle, m is index of refraction ofthe optic 1310, and n₂ is index of refraction of the materialsurrounding the optic (e.g., air 1314 or dental hard tissue 1316).

For example, in a certain exemplary embodiment the optic comprises CVDdiamond, having an index of refraction of approximately 2.38 and thelaser source comprises a CO₂ laser, having a wavelength of 9.3 μm. Inthis case, the critical angle for TIR between the CVD diamond and thedental enamel is approximately 42° and a maximum penetration depth 1320of the evanescent wave using an angle of incidence slightly greater thanthe critical angle (e.g., 43°) is 5 μm. As optical penetration depth(due to absorption) of 9.3 μm radiation in dental enamel (i.e.,hydroxyapatite) (e.g., ˜2 μm) is less than the evanescent wavepenetration depth 1320, much of the radiation 1312 will be absorbed intothe dental hard tissue 1316 under these conditions.

FIG. 13C schematically represents a second technique for contactcoupling radiation 1312 into dental hard tissue 1316. In the secondtechnique, radiation 1312 is refracted into the dental hard tissue 1316.This phenomenon is sometimes understood as frustrated internalreflection (e.g., frustrated total internal reflection [FTIR]). In oneembodiment of the second technique, the optic 1310 has an index ofrefraction that is less than the index of refraction of the dental hardtissue. For example, in some exemplary embodiments a lower index opticmaterial is used (e.g., UV fused silica [n=1.5]) and index of refractionfor dental enamel is about 1.6. In this case, radiation 1312 isrefracted into the dental hard tissue 1316.

For example, a certain exemplary embodiment employs a UV laser sourcehaving a 355 nm wavelength and a fused silica optic having an index ofrefraction of 1.5. In this case, the critical angle for the optic 1310using air (n=1) as the surrounding material is about 42° and evanescentfield penetration 1322 within air at the optic boundary using an angleslightly greater (43°) than the critical angle is approximately 0.3 μm.However, when the optic 1310 comes in contact with the dental hardtissue 1316, the radiation 1312 is refracted into the dental hardtissue, in a manner that can be understood according to Snell's law, andabsorbed by the dental hard tissue. In some circumstances, the case of aUV laser source (355 nm) and a fused silica optic (n=1.5) isadditionally advantageous. This is because UV light can cause geneticdamage, which can cause cancer (e.g., skin cancer). For this reason,application of UV radiation should be precisely directed only to dentalhard tissue and not to soft tissue (e.g., skin and mucosa). The UVradiation will undergo TIR reflection within the optic when surroundedby air and therefore stay confined within the optic and not directed totissue not in contact with the optic 1310. Additionally, under somecases the UV light will not fully couple out of the optic 1310 even whenplaced in contact with oral soft tissue. Oral soft tissue has an indexof refraction (at UV wavelengths) that is near that of water and istypically less than that of fused silica, (e.g., 1.4). For example, arepresentative critical angle for total internal reflection between softtissue and a fused silica optic 1310 is 69° and a maximum evanescentwave penetration depth 1322 for a 355 nm beam with a 70° angle ofincidence is approximately 0.3 μm. A cell width is approximately 10 to30 μm. Therefore, the UV radiation does not penetrate cell nuclei; and,a likelihood of genetic damage to the soft tissue is greatly reduced,even when the optic is placed in direct contact with soft tissue.

In one embodiment, the second technique as outlined in FIG. 13C anddescribed as frustrated internal reflection can also occur when theindex of refraction of the dental hard tissue is less than that of theoptic 1310. Frustrated internal reflection also occurs where the angleof incidence is smaller than the critical angle between the index ofrefraction for the optic 1310 and the dental hard tissue 1316. Forexample, returning to the example above with a 9.3 μm radiation 1312 anda CVD diamond optic 1310 with an index of refraction of 2.38, a criticalangle between the optic and air is about 25°, a critical angle betweenthe optic and oral soft tissue is about 36°, and a critical anglebetween the optic 1310 and the hard tissue 1316 is about 42°. This meansthat radiation propagating at an angle of incidence between 36° and 42°will experience total internal reflection (TIR) when the optic 1310 isin air or in contact with oral soft tissue and frustrated total internalreflection (FTIR) when the optic 1310 is placed in contact with dentalhard tissue 1316. Tissue specific penetration of radiation is thereforean advantage of certain embodiments, although addition advantages doexist. For example, use of a contacting laser delivery device isexpected to be more easily adapted to use in a dental operatory, wheremost dental tools are used in contact with dental hard tissue.

Another advantage of certain embodiments is that contact coupling ofradiation can be used to treat areas of dental hard tissue that aconventional free space laser treatment cannot. For example,inter-proximal dental regions (i.e., space between the teeth) are commonlocations for caries formation and a location that convention laserscannot always irradiate, as there is no free space direct line of sightof the inter-proximal regions. In certain exemplary embodiments, anoptic 1410 is configured to access and deliver radiation 1411 tointer-proximal dental hard tissue 1412. FIG. 14 schematicallyillustrates an optic 1410 between a first tooth 1414 and a second tooth1414. In some embodiments, the optic 1410 comprises a rod having adiameter (e.g., less than 2 mm, less than 1 mm, or less than 0.5 mm)selected to fit inter-proximally between teeth. In some embodiments, therod comprises a hard material (e.g., diamond or quartz) so that it doesnot break during use.

FIG. 15 illustrates an optical path 1500, in accordance with anembodiment. A collimated radiation, for example a laser beam 1510,having a Gaussian energy profile 1512 is directed incident a first focusoptic 1514. The first focus optic 1514 converges the radiation anddirects the radiation into a homogenizer 1516. Exemplary homogenizersinclude diffractive optical element (DOE) homogenizers, transmissivediffusers, reflective diffusers, and rod homogenizers. An exemplary DOEhomogenizer for infrared wavelengths is Part No. HM-212-A-Y-A fromHolo/OR of Ness Ziona, Israel. An exemplary rod homogenizer for UVwavelengths is a 2 mm clear aperture fused silica homogenizing rod,Edmund Optics Part No. 63-092 from Edmund Optics of Barrington, N.J.,U.S.A. Typically, the radiation 1510 diverges as it exits thehomogenizer. After exiting the homogenizer 1516, the radiation has amore homogenized energy profile (e.g., flat-top, top-hat, orsuper-Gaussian) 1518. A second focus optic 1520 converges the radiation1510 again and directs it into a coupling optic 1522. Exemplary couplingoptics 1522 include prisms, dove prisms, waveguides, rods, ATR prisms,etc. An exemplary dove prism is a 10 mm dove prism Part No. 85-156 fromEdmund Optics. According to some embodiments, the optical path 1500 alsocomprises a waveguide or fiber optic. An exemplary prism assembly thatadditionally comprises a fiber optic is Diamond Probe, Part No. DMP-PRBfrom Harrick Scientific Products of Pleasantville, N.Y., U.S.A.Radiation is at least partially transmitted into a dental hard tissue15624 when it is placed in contact with the coupling optic 1522.Finally, the radiation 1510 not transmitted into the dental hard tissueexits the coupling optic 1522 and is directed toward either a sensor ora beam dump 1526. Irradiative treatment of the dental hard tissue 1524raises the temperature of the surface of the dental hard tissue to anelevated temperature (e.g., between 400° C. and 1200° C.) momentarily.For this reason, the coupling optic in some embodiments is constructedfrom a material that can handle these high temperatures (e.g., diamond,sapphire, fused silica, and quartz). Alternatively, in some embodiments,the coupling optic is consumed during each treatment and the material isinexpensively produced, for example optical salts (e.g., bariumfluoride, magnesium fluoride, and calcium fluoride).

Additionally, in some certain exemplary embodiments, the coupling opticis actively cooled to prevent bulk heating of the dental hard tissue(e.g., tooth) and/or the optic itself. It is widely accepted that inorder to prevent the possibility of thermal damage to a tooth, nerveswithin a pulpal chamber of the tooth must not be raised to a temperaturegreater than 5.5° C. above normal. Delivering irradiative energy to thetooth can result in bulk heating of the tooth. In order to preventthermal damage, in some embodiments, contact cooling of the tooth isachieved by way of cooling the coupling optic. FIG. 16 illustrates anembodiment in which a cooling system 1600 cools a coupling optic 1610.The coupling optic 1610 is at least partially enclosed within a fluidicpathway through which a coolant 1614 flows. In some cases, the fluidicpathway provides a seal about the coupling optic, such that the coolantcan come in direct contact with the coupling optic 1610. Alternatively,the fluidic pathway 1612 is entirely separate from the coupling optic1610, such that the coolant cools the fluidic pathway 1612 and then thefluidic pathway 1612 cools the coupling optic 1610. The coolant 1614circulates within the fluidic pathway 1612 using a pump 1616. Thecoolant is cooled by a chiller 1618. Exemplary chillers include Peltierjunctions. The coolant 1614 is chilled to a temperature that is lowenough to prevent bulk heating of the dental hard tissue (e.g., tooth)and not too low to cause discomfort for the patient (e.g., in a rangebetween −20° C. to 20° C.).

Although, exemplary systems disclosed above describe use of a lasersource to deliver radiation for treatment, non-laser-based systems areenvisioned. For example, in some embodiments, radiation is non-coherent.The non-coherent radiation in some cases is generated by a non-coherentlight source, for example a flash lamp. In a certain specific exemplaryembodiment, UV non-coherent radiation is generated by one or more of aXeon flash lamp, a Xeon lamp, a Mercury-Xeon lamp, and a Deuterium flashlamp.

Recurrent Payment to Defray Laser System Ownership Costs

In order to minimize upfront costs associated with installation of adental laser system, a distribution system is disclosed that allows forthe secure distribution of coupons representative of individual (ormultiple) uses of the dental laser system, thus achieving a recurrentpayment system. Additionally, systems and methods are disclosed toensure that unauthorized use of the dental laser system is minimized. Inorder to successfully minimize unauthorized use, techniques are employedthat result in a cost associated with circumventing authorized use(e.g., through counterfeiting, hacking, or fraud) exceeding a costassociated with purchasing authentic coupons. Said another way, in acommercially successful practice of the disclosed distribution systemand methods, a price of the coupons (representing a single use of thelaser system) is interrelated with a level of technological difficultyto circumvent the coupons. Description of systems and methods thatsupport making, distributing, and using these coupons are describedbelow.

FIG. 17A illustrates a distribution system for preventative laser andfluoride treatment in accordance with one embodiment. A hermeticallysealed package 1700 is shown in FIG. 17A fully intact. This package isdistributed to dental practices like other dental supplies (e.g.,consumables). In many embodiments, many units of the package 1700 aregrouped together and distributed to dental practices in multipacks(e.g., cases).

FIG. 17B illustrates the package 1070 after being opened. In accordancewith one embodiment, the package contains a fluoride treatment dosage1710, a fluoride applicator 1712, and a machine-readable code 1714.Exemplary fluoride dosages 1710 include fluoride varnishes, fluoridegels, fluoride pastes, fluoride fluids, and fluoride foams. The fluoridedosage 1710 comprises any number of fluoride compositions known toeffectively treat dental surfaces, for example Sodium Fluoride (NaF) andStannous Fluoride (SnF₂). Exemplary applicators 1712 include swabs,needles, syringes, and dental trays (not shown). The machine-readablecode 1714 is configured to be read by the dental laser system. In oneembodiment, the machine-readable code 1714 represents one (or more)dental laser treatment(s). Exemplary forms of the machine-readable code1714 include a barcode, a 2D barcode, a magnetic strip (not shown), atransponder device (not shown), a microchip (not shown), and aradio-frequency identification (RFID) tag (not shown). Typically, themachine-readable code 1714 represents a coupon for one or more lasertreatments and without a valid coupon (or number of coupons) the lasertreatment cannot be performed.

FIG. 18A illustrates a preventative dental laser system 1800 inaccordance with one embodiment. The dental laser system 1800 typicallyincludes a console 1810. Within the console 1810 a laser source and alaser controller are housed. An exemplary laser source is a carbondioxide (CO₂) laser, for example HPP DL-500 from Access Laser ofEverett, Wash., U.S.A. Additional exemplary laser sources include carbondioxide (CO₂) lasers, carbon monoxide (CO) lasers, excimer lasers, fiberlasers, diode pumped solid state (DPSS) lasers, and semiconductorlasers. Typically, the radiation source is selected to generate aradiation 1710 having a wavelength that is well absorbed (e.g., has anabsorption coefficient greater than 1 cm⁻¹, 100 cm⁻¹, or 1,000 cm⁻¹) bythe dental hard tissue 1712. Exemplary wavelengths include wavelengthsin either of a first range between 200 and 500 nm and second rangebetween 4 and 12 μm. The laser source generates a laser beam, which isdirected via a beam delivery system 1812 to a hand piece 1814. Exemplarybeam delivery systems 1812 include articulated arms, hollow waveguides,and fiber optics. The hand piece 1814 is configured to be usedintra-orally to deliver the laser beam to surfaces of dental hard tissuefor treatment. The laser controller is configured to control at leastone parameter of the laser beam during treatment. Exemplary laserparameters include pulse energy, average power, peak power, pulseduration, and repetition rate.

The laser system 1800 also includes a code reader 1816, which isconfigured to read the machine-readable bar code 1714. In oneembodiment, the code reader 1816 employs a machine vision system, whichtakes a digital image of the machine-readable code 1714 and recognizesthe machine-readable code 1714. In some cases, the machine vision systemincludes a lens assembly, an optical sensor (e.g., a charge-coupleddevice [CCD] or a complementary metal-oxide semiconductor [CMOS]), and avision processor. The vision processor is configured to recognize a codewithin the digital image of the machine-readable code 1714. Exemplarysoftware resources for reading the machine-readable code in a digitalimage include Data Matrix within OpenCV project. Alternatively, themachine-readable code 1714 can be stored on another device, for examplea one-wire chip, an RFID tag, a film, and a magnetic strip. So, inalternative embodiments, the code reader 1816 comprises one or more of aone-wire chip reader (not shown), an RFID tag reader (not shown), a filmreader (e.g., camera with illumination system), and a magnetic stripereader (not shown). In order for the machine-readable code 1714 tosuccessfully prevent fraudulent use of the laser system 1800, the code1714 is verified.

A verification system 1836, in accordance with one embodiment, isillustrated in a block diagram in FIG. 18B. A code 1714 is first read bya code reader 1816. The code reader 1816 recognizes the code andcommunicates the code to the verification system 1836. The verificationsystem typically comprises a processor that is local to the dental lasersystem 1800. In some cases, the verification system employs an internalverification system 1837 only, which verifies the code locally. Forexample, in accordance with one embodiment a one-wire authenticationchip and only an internal verification system 1837 is used. In analternative embodiment, the code 1714 comprises a digital signature(e.g., cryptocurrency) that exists within memory (e.g., non-volatilememory) and the code reader comprises a processor. In some situations,the code 1714 is verified by way of remote systems.

The verification system 1836 can use one or more networks 1838.Exemplary networks include local area networks (LAN), wide area networks(WAN), wireless networks (WiFi), closed area networks (CAN), etc. Inaccordance with one embodiment, the verification system communicates thecode 1714 with a central server 1840 by way of one or more networks1838. In some cases, communication between the verification system 1836and the server 1840 is encrypted (e.g., symmetric encryption or publickey/private key encryption). In some cases, the verification system 1836includes additional information in its communication with the centralserver 1840, for example a timestamp, a unique system identifier, orinformation regarding the laser treatment. The central server 1840 thencompares the information as communicated from the verification system1836 and determines an authenticity of the code 1714 and determines ifthe code 1714 is valid (e.g., has not been used before). Once thecentral server 1840 and the verification system 1836 verify the code,the verification system 1836 allows a laser treatment to be performed.In alternative embodiments, the determination performed in part by thecentral server is performed using one or more nodes 1842A-C. The nodes1842A-C, in accordance with one embodiment, are communicated to by theverification system 1836 and are queried to learn if the code 1714 isauthentic and unused. In some cases, a majority of node responses areused to verify the code and conflicts between nodes are satisfied inaccordance with the principle of “proof of work” (for example, with ablockchain method). In some embodiments, each laser treatment system1800 comprises a verification node.

Generally, the verification system 1836 only allows the laser controller1844 to operate the laser source 1846 after the machine-readable code1714 has been verified. In some cases, the verification system 1836budgets a use of the treatment system 1800. Certain exemplary budgetsare for one treatment, a certain amount of time, a certain amount oflaser energy delivered, or a certain amount of energy consumption by thelaser. In some cases, an interlock 1848 is closed by the verificationsystem 1836 post-verification to permit a budgeted use. The verificationsystem 1836 in some case communicates directly with (or is coupled to)the laser controller 1844 in order to prevent a simple defeat of theinterlock 1848, which would allow a circumvention of the verificationsystem 1836 (and an unbudgeted use). For example, in a certainembodiment, the laser controller 1844 comprises a field programmablegate-array (FPG) (e.g., Xilinx Zynq) and the verification system 1836comprises a one-wire authentication system (e.g., MAXREFDES44 #reference design from Maxim Integrated of San Jose, Calif., U.S.A.) toverify the machine-readable code and communicate directly with the lasercontroller 1844.

After verification (or simultaneously with verification, or prior toverification), the verification system 1836 also prevents futureverification of the same code 1714. In one embodiment, prevention offuture validation is achieved by submitting to the central server 1840or one or more nodes 1842A-C that the machine-readable code 1714 is nolonger valid. In one embodiment, preventing future verification of themachine-readable code 1714 entails deleting, destroying, disrupting,voiding, or overwriting the machine-readable code 1714. For example, insome cases the machine-readable code 1714 is contained within a one-wireauthentication chip and during reading of the chip, the machine-readablecode is overwritten, for example to zero. Although many techniques aredescribed to allow use of the system only after verification of the code1714, unauthorized use of the system 1800 is always a technicallyfeasible possibility. Certain exemplary attacks that could be used tocircumvent the verification system 1836 include“man-in-the-middle,”“replay attack,” and “chip rip.” As each couponneeds to be relatively cheap to produce (e.g., much less than a cost toperform one treatment), not all potential attacks can be realisticallyredressed. For this reason, further systems are employed, in someembodiments, to monitor system use.

FIG. 18C illustrates a block diagram of additional subsystems of thedental laser system 1800, in accordance with one embodiment. A powersupply (e.g., direct current [DC] power supply) 1860 powers the lasersource 1846. Located schematically between the power supply 1860 and thelaser source 1846 is an electricity meter 1862. The electricity meter1862, in some embodiments, measures an amount of electricity (e.g.,energy [power multiplied by time]) that is consumed by the laser source1846. The measured electrical energy is an indication of laser on-timeand therefore use of the laser treatment system 1800. The laser source1846 generates a laser beam 1864 during laser treatment. In accordancewith one embodiment, the laser beam is continuously monitored by a laserpower meter 1866 (e.g., thermopile or photodetector). In some cases, asmall proportion of the total laser beam 1864 is “picked-off.” The smallproportion of the laser beam is then measured as representative of thetotal laser beam energy by the laser power meter 1866. In some cases,the measured value from the laser power meter 1866 is used as anotherindication of laser on-time and therefore laser treatment system use.

A processor receives the measurements form one or both of theelectricity meter 1862 and the laser meter 1866. The processor in someembodiments, logs the measurements, for example, either locally, or onthe central server 1840 and/or a de-centralized node 1842A by way of oneor more networks 1838. Logging measurements that are indicative of useallows for an understanding of actual treatment system use time to beestimated. The estimated actual system use time can later be comparedwith verified use (e.g., number of verified coupons). Just asdiscrepancies in exit-polling and vote count indicate voter-fraud,discrepancies between estimated actual system use and verified systemuse (e.g., coupon use count) indicate fraudulent use of the lasersystem.

FIG. 19 is a flow chart 1900, which illustrates a method forpreventative dental treatment, in accordance with one embodiment. First,a machine-readable code is read 1910. In some embodiments, themachine-readable code represents a coupon for one (or more) lasertreatments. In some embodiments, the machine-readable code is read by abarcode reader. Alternatively, the machine-readable code is read by oneor more of: a magnetic stripe reader, a radio-frequency identification(RFID) reader, a transponder reader, and a microchip interface (e.g., aone-wire device). The machine-readable code is read 1910 and then themachine-readable code is verified 1912. In some cases, themachine-readable code is verified by determining its inclusion in a listof verifiable machine-readable codes. In one embodiment, themachine-readable code is encrypted, for example by using one or more ofa symmetric encryption system and an asymmetric encryption method, andverification of the machine-readable code includes decryption. In somecases, the machine-readable code is verified remotely (e.g., over anetwork), for example by a central server or one or more nodes. In somecases, communication over the network (during verification) is furtherencrypted between a verification system local to the treatment systemand the central server or one or more nodes. In some cases, the centralserver and one or more decentralized nodes comprise ledgers (e.g.,decentralized ledger). The decentralized ledgers are used to trackissuance, verification, transfer, and use of coupons. In some cases,decentralized ledgers that demonstrate the greatest amount ofcomputational work are trusted over contradicting decentralized ledgersthat demonstrate achieving less computational work. A certain exemplarysystem for decentralized (“trustless”) ledgers is a blockchain. In someembodiments, digital signatures related to individual treatment systemsare used to ensure additions to the ledger(s) are honest. For example,in some cases a private key associated with an individual treatmentsystem is used to encrypt a digital signature, which is used in one ormore ledgers. In some embodiments, the digital signature sent from anindividual treatment system also includes additional information thatcan aid in verification of honest use of coupons.

Once, the machine-readable code is verified (for example, verified as anunspent and otherwise valid coupon representing a laser treatment and/oragreed by one or more ledgers that the system verifying has a coupon touse), a laser treatment is budgeted for by the system and a lasertreatment is performed 1914. A laser treatment is represented inaccordance with one embodiment in FIG. 19 .

Firstly, the laser treatment begins by generating a laser beam 1914A.The laser beam is typically generated using a laser source. Exemplarylaser sources include: CO₂ lasers having a wavelength between 9 μm and11 μm, fiber lasers, diode pumped solid state lasers (DPSS), Q-switchedsolid-state lasers (e.g., third harmonic Nd:YAG lasers having awavelength of about 355 nm), Excimer lasers, and diode lasers. Commonlythe laser beam has a wavelength that is well absorbed (e.g., has awavelength having an absorption coefficient greater than 1 cm⁻¹, 100cm⁻¹, or 1,000 cm⁻¹) by a dental hard tissue. The laser beam is thendirected toward a surface of the dental hard tissue 1914B. In someembodiments, the laser beam is directed into an intra-oral cavity usinga beam delivery system. The laser beam is often directed within theintra-oral cavity using a hand piece. In some embodiments, the laserbeam is converged, using a focus optic, as it is directed toward thedental hard tissue, such that it comes to a focal region proximal thesurface of the dental hard tissue. Exemplary focus optics include lenses(e.g., Zinc Selenide Plano-Convex lenses having an effective focallength of 200 mm) and parabolic mirrors. In some embodiments, the laserbeam is scanned as it is directed toward the surface of the dental hardtissue by a beam scanning system. Exemplary beam scanning systemsinclude Risley prisms, spinning polygon mirrors, voice coil scanners(e.g., Part No. MR-15-30 from Optotune of Dietikon, Switzerland),galvanometers (e.g., Lightning II 2-axis scan head from CambridgeTechnology of Bedford, Mass., U.S.A.), and a gantry with a translatingfocus optic. Scanning methods related to dental laser systems aredescribed in U.S. Pat. No. 9,408,673 by N. Monty et al., incorporatedherein by reference.

Finally, a parameter of the laser beam is controlled 1914C. Typically,the parameter of the laser beam is controlled in order to heat a portionof the surface of the dental hard tissue to a temperature within a rangeof 400° C. to 1300° C. Exemplary laser parameters include pulse energy,pulse duration, peak power, average power, repetition rate, wavelength,duty cycle, laser focal region size, laser focal region location, andlaser focal region scan speed. During laser treatment a laser beam isgenerated and directed toward a surface of dental hard tissue.Typically, the laser beam is pulsed at a prescribed repetition rate andhas a certain pulse duration. Alternatively, pulses can be delivered ondemand, and the pulse duration can vary (for example, to control heatingof the surface of the dental hard tissue). As a result of theirradiation of the surface, a temperature of the surface rises typicallyto within a range between 400° C. and 1300° C. momentarily (e.g., duringa duration of the laser pulse) and cools back to a normal temperaturerange (e.g., within a range of 20° C. and 60° C.). As a result of themomentary temperature rise biological materials previously on or adheredto the surface of the dental hard tissue (e.g., pellicle, bio-film,calculus, and tartar) are at least partially removed and/or denatured.In some embodiments, this removal of biological materials substantiallycleans the teeth and the laser treatment replaces other tooth cleaningprocedures typically performed during a dental check-up (e.g., scalingand polishing). Additionally, as described above, heating the surface ofthe dental hard tissue removes impurities (e.g., carbonate) from thedental hard tissue and makes the dental hard tissue less-susceptible toacid dissolution (e.g., demineralization). In some embodiments, thelaser treatment is performed after other treatments during a dentalvisit. For example, in some cases the dental laser treatment isperformed 1914 only after one or more of removal of plaque and tartar(with one or more manual instruments), professional flossing, and powerpolishing (i.e., dental prophylaxis). This order of steps in some casesis considered advantageous, as the laser treatment purifies only anouter portion (e.g., 2 μm thick) of the dental enamel and some dentalcleaning treatments can remove a portion of dental enamel (e.g., powerpolishing), potentially removing the enamel which has just beenpurified. After, the dental laser treatment has been performedadditional steps are taken for the preventative dental treatment 1900,in accordance with one embodiment.

Next, a dental fluoride treatment is applied to at least a portion ofthe surface of the dental hard tissue 1916. The dental fluoridetreatment dose in one embodiment has a form of a gel, a varnish, apaste, or a foam. The dental fluoride treatment dose in one embodimentcomprises at least one of Sodium Fluoride, Stannous Fluoride, TitaniumTetrafluoride, Acidulated-Phosphate Fluoride, and Amine Fluoride. In oneexemplary embodiment, the fluoride dose has a varnish form and isapplied to a portion of a surface of the dental hard tissue using anapplicator. In some embodiments, application of the dental fluoride dose1916 is performed after the dental laser treatment. In some cases, thisorder is considered advantageous as plaque, pellicle, and biofilm aresubstantially removed from the surface of the dental hard tissue duringthe laser treatment.

Future verification of the machine-readable code is prevented 1918. Forexample, by rendering unreadable the machining readable code (e.g.,overwriting a one-wire chip or RFID authentication tag). In anotherexample, the machine-readable code is indicated as invalid (e.g., on alist or ledger). In some cases, RFID authentication tags and/or one-wireauthentication chips are too expensive to use to represent a single useof the system 1800, and instead barcodes (e.g., printed on paper orfilm) are used to represent a coupon for one or more treatments. Thisdrastically reduces the cost of manufacture for coupons, but also addsnew difficulties to authentication.

A number of systems and methods can be used for verification of validcoupons and rejection of non-valid coupons. A number of exemplarysubsystems are described in the following paragraphs to aid in thepractice of this invention. An exemplary coupon verification system andmethod is shown in FIG. 19B. In this case, a coupon issuer 1920 issues acoupon 1922 and generates a machine-readable code. The coupon issuer1920 uses a coupon identification number (CPID) and an encryption key1926 (e.g., private key) to generate a digital signature whichrepresents a coupon 328. In an exemplary embodiment, the CPID 1924comprises a digest and is generated, by the coupon issuer, from amessage, using a cryptographic hash algorithm (e.g., SHA-3) or apseudo-random number generating algorithm. In some embodiments, the CPID1924 is documented and grouped by manufacturing lots, case, or packageserial number. The coupon (digital signature) 1928 is then encoded intoa machine-readable code (e.g., barcode, RFID, magnetic strip, a digitalsignature, etc.) and the machine-readable code is sequestered (e.g.,packaged with a single use fluoride treatment) and ultimatelydistributed to a treatment system.

An exemplary coupon reading and decrypting system is described withreference to FIG. 19C. The machine-readable code 1922 is ultimately readby a reader 1930. An encryption key 1932 (e.g., public key or symmetrickey) is used to decrypt the machine-readable code (for example, with adecryption system 1933) yielding the CPID 1924. The CPID 1924 can thenbe verified. For example, in a simple case, the CPID 1924 is generatedusing an algorithm (e.g., SHA-2 or SHA-3) which is duplicated on thetreatment system; and, the verification system 1934 verifies a veracityof the CPID 1924 by an accordance between the CPID and the algorithm. Insome embodiments, the verification system 1934 verifies that the CPID1924 is valid using one or more authorities.

A coupon authority 1940 is described in reference to FIG. 19D. In thesimplest case the coupon authority only tracks coupon identificationnumbers 1924 and coupon validity 1942. In one embodiment, the couponauthority 1940 also tracks additional information 1950. The couponauthority 1940 in some cases is local to the verification system 1836within the treatment system 1800. Alternatively, the coupon authority1940 is remote. The coupon authority in some cases is decentralized anda local coupon authority 1940 exists within the treatment system. Insome cases, the coupon authority only tracks spent (non-valid) coupons.In one embodiment, verification of the coupon includes querying thecoupon authority 1940.

In another exemplary embodiment, coupons are distributed electronicallyusing a system like bitcoin. In this system, a stock of couponspossessed by each individual treatment system is tracked by a system ofdecentralized ledgers (e.g., blockchain). In this case, verification ofa coupon includes transferring the coupon (for example, to thedistributor, to the coupon issuer, to a specified coupon collector, orto a void) and verifying that the transfer was recorded in one or moreledgers. In some cases, the transfer includes broadcasting a digitalsignature (for example, encrypted by a private key associated with thetreatment system 1800) that includes a message comprising the transfer.In some cases, the message also includes additional information.Exemplary additional information includes, a date and time of treatment,a total energy consumed by laser system (lifetime), a total energygenerated by laser system (lifetime), data related to themachine-readable code, a total number of treatments performed by thelaser system, etc. In some certain exemplary embodiments, the couponsare digital in form and are distributed electronically.

According to one embodiment, a machine-readable code 1714 is includedwithin a consumable (e.g., single-use) hand piece attachment. FIG. 20Aillustrates a view of a dental laser hand piece 2010 with an attachabletip 2012 attached. In some cases, the attachment 2012 is provided withina hermetically sealed package with a single-use fluoride dose. Theattachment 2012 and hand piece 2010 of FIG. 20A is shown in across-sectional view in FIG. 20B. Within the hand piece 2010 a focusoptic 2014 is located to converge a laser beam. Opposite the focus optic2014, a reflector 2016 is positioned within the attachment 2012. Thereflector 2016 has a high reflectivity (e.g., at least as great as 50%)at a wavelength of the laser beam. The reflector 2016 is positioned toreflect the converging laser beam out of an aperture 417 within theattachment 2012. In some cases, the attachment is made from an ejectionmolded polymer. The reflector 2016, in some embodiments, is coated on asurface of the attachment 2012. Alternatively, the reflector 2016comprises a separate substrate from the attachment 2016. Exemplarycoatings for the reflector 2016 include broadband coatings (e.g.,silver, protected silver, and gold) and dielectric coatings. Theattachment 2012, in certain exemplary embodiments shown in FIGS. 20A-B,is attached to the hand piece 2010 using a canted coil spring 2018(e.g., Bal-Seal of Foothill Ranch, Calif. U.S.A.). The canted coilspring 2018, in some cases can also provide an electrical connectionbetween a one-wire authentication chip 2020 storing the machine-readablecode and an electrical connection in the hand piece 2022, which isultimately connected to a processor within the laser treatment system.An exemplary one-wire authentication chip is Part No. DS28C50 from MaximIntegrated of San Jose, Calif., U.S.A. The attachment 2012 shown inFIGS. 20A-B helps direct the laser beam intra-orally by reflecting thelaser beam. In other embodiments, a consumable attachment is providedthat does not reflect the laser beam.

Referring now to FIG. 21A a hand piece 2110 is shown with a consumablesheath attached 2112, in accordance with one embodiment. The consumablesheath 2112 allows for intra-oral use without need for sterilization ofthe hand piece 2110 in between patients. This is because only the sheath2112 (during normal use) comes into contact with a patient. A new sheaththerefore is used with each patient (and, therefore each new treatment).FIG. 21B illustrates a cross-sectional view of the hand piece 2110 andthe sheath 2112 of FIG. 21A. A focus optic 2114 is positioned within thehand piece 2110. The focus optic 2114 is configured to converge a laserbeam. Opposite and down-beam from the focus optic 2114 is a reflector2116. Unlike the embodiment illustrated in FIGS. 20A-B, the reflector2116 is not a part of the consumable attachment (the sheath) 2112.Instead, the reflector 2116 is an integrated component of the hand piece2110. The reflector 2116 in some cases is a separate part from the restof the hand piece 2110 and is therefore removable for maintenance.However, the reflector 2116 in this case is not intended for removalwith each treatment. The reflector is configured to reflect theconverging laser beam out of an aperture 2117 within the sheath 2112. Insome embodiments, the sheath 2112 is attached to the hand piece in FIG.21B by a snap feature (not shown). Alternative attachment of the sheathand the consumable attachment are also envisioned, for examplefasteners, threads, clamps, magnets, and O-rings. The sheath 2116, insome embodiments, comprises a one-wire authentication chip 2118. Thechip includes the machine-readable code. The hand piece 2110 comprises apogo pin 2120 which is configured to make an electrical contact betweenthe chip 2118 and an electrical connection 2122 within the hand piece2110. The electrical connection within the hand piece communicates witha processer in the laser treatment system, which verifies themachine-readable code. In another exemplary embodiment, the sheathcomprises the machine-readable code in a different medium, for example abarcode, a 2D barcode, or an RFID tag.

To aid in practice of the claimed invention and parameter selection atable is provided below with exemplary ranges and nominal values forrelevant parameters.

Parameter Min. Max. Nom. Repetition Rate 1 Hz 10 KHz 1 KHz Pulse Energy1 μJ 1 J 10 mJ Focal Region Width 1 μm 10 mm 1 mm Fluence 0.01 J/cm² 1MJ/cm² 1 J/cm² Wavelength 200-500 nm 4000-12000 nm 10.6 μm NumericalAperture 0.00001 0.5 0.01 (NA) Focal length 10 mm 1000 mm 200 mm AveragePower 1 mW 100 W 1 W Peak Power 50 mW 5000 W 500 W Scan Speed 0.001 mm/S10 mm/S 100,000 mm/S ScanLocation 0 0.5 × Focal Region 10x Focal RegionSpacing Width Width Machine Readable Barcode, 2D Barcode, RFID Tag,Authentication Chip (e.g., One- Code Mediums Wire), Digital, SoftwareToken (e.g., Google Authenticator), Paper Token (e.g., TransactionAuthorization Number [TAN]), a consumable intra-oral component (e.g.,hand piece attachment), and a film. Machine Readable One Time Password(OTP), Hash Message Authentication Code, Code Contents Digest,Transaction Authorization Number (TAN), are Encoded; are Encrypted; areObfuscated (i.e., identification of valid coupons is held in secret);and, a digital signature. Fluoride Treatment Sodium Fluoride, StannousFluoride, Titanium Tetrafluoride, Ingredients Acidulated-PhosphateFluoride, and Amine Fluoride

FIG. 22 illustrates a block diagram 2200 of a hardware configurationaccording to a certain exemplary embodiment. The hardware comprises asingle board computer (SBC) 2210 (e.g., RaspberryPi Compute Module 4Lite configured with a quad-core ARM Cortex-A72 processor). The SBC 2210in some versions runs a Linux operating system. Software for the SBC2210, including the operating system, in some cases is stored on anexternal write once read many (WORM) memory 2211 (e.g., a Flexxon 32 GBmicroSD WORM). The WORM 2211 storage allows data to be stored memorywithout risk of erasure. In some embodiments, a barcode reader 2212 isconnected to the SBC and is configured to read a barcode, for example ahigh capacity 2D (HC2D) barcode. In some exemplary versions, the barcodereader 2212 comprises a digital camera and illuminator that togethercapture an image of a barcode. In some versions, the camera andilluminator are triggered to capture by a user interface button, whichis hardwired to a GPIO digital input of the SBC 2210. An exemplarycamera is a SONY IMX219 sensor that may be connected to the SBC 2210 byway of a dedicated standard CSI interface. The SBC 2210 communicates toa laser controller 2214, for example a HALaser E1701A. In someembodiments, the SBC communicates with the laser controller 2214 by wayof an ethernet connection. The laser controller 2214 directly controls alaser treatment system 2216 and requisite treatment parameters forsuccessful treatment. A user interface 2218, for example a footswitch,is also communicative with the laser controller 2216, and allows theclinician to perform a laser treatment.

The hardware configuration described in the block diagram 2200 above canbe used, in certain exemplary embodiments, to (1) read a coupon; (2)decode and validate a coupon; and, (3) perform a preventive lasertreatment. First, (1) a coupon is read. In certain cases, the couponwill comprise a 2D barcode, which is embellished upon a consumablecomponent and reading the barcode will include use of a specializedbarcode reader hardware 2212 located inside the device. Barcode readinghardware will, in some cases, include a camera and an illuminator. Ahigh capacity 2-dimensional (2D) (HC2D) barcode (e.g., QR Code orsimilar) can be used to maximize the amount of information containedwithin the barcode. Once the coupon is read, it is time to (2) decodeand validate the coupon. Each individual coupon must be used only onceand therefore, in some versions, earlier uses of previous coupons arerecorded and compared with each new coupon. Additionally, the veracityand validity of each coupon must be scrutinized. In certain exemplaryembodiments, each coupon comprises a digital signature. The origin ofthe digital signature is decrypted with a key (e.g., public key) and theauthenticity (i.e., known origin and unalteredness) of the resultingdecrypted message is verified, for example by a one-way HASH algorithm.Once, the message is successfully decrypted and verified by HASHalgorithm, it may be assumed that the coupon is valid (i.e., it trulyrepresents one laser treatment). In some versions, the message is thencompared to an enumerated list of previous messages already used inorder to prevent double spending. A write once read many (WORM) memory2211, in some versions, is employed to store the enumerated couponmessages representing spent coupons. Once the coupon is validated andspent (e.g., the message is saved to WORM memory), a laser treatment isauthorized. Then, (3) the SBC 2210 allows the user to perform the lasertreatment, for example by sending laser control parameters to the lasercontroller board 2214, which operates the laser system during treatment.Without these laser control parameters, the laser controller board 2214is unable to operate the laser system 2216 and no treatment may beperformed.

FIG. 23 illustrates a flowchart 2300 describing a coupon authenticationmethod, according to certain embodiments. First a machine-readable codeis acquired 2310. For example, in some exemplary cases a barcode isscanned. The machine-readable data is then decrypted 2312, by way of akey. In some embodiments, the key is an asymmetric key (e.g., publickey). By being able to decrypt the data from the barcode with a specificpublic key, the controller is able to ensure that the decrypted contentsare from a specific source in possession of a private key. In this case,an authorized coupon issuer will generate and encrypt the coupons usinga private key. The coupon will be assumed to be encrypted by theauthorized coupon issuer if it is decrypted using a public key to theprivate key of the authorized coupon issuer. Within certain embodiments,the decrypted contents will contain a message and a digest. The message,in some cases, comprises a coupon code and the digest is the value ofthe message when it is run through a HASH algorithm. The decryptedmessage is run then through a specified HASH algorithm. The outputresults of the HASH algorithm are then compared to the decrypted digest2314. If the two are equal, it is probable that the coupon has beenunaltered, since it was encrypted by the authorized coupon issuer. Thenow validated message (e.g., coupon code) is then searched for on awrite once read many (WORM) memory storage 2316. In some embodiments,the WORM is configured to store every “spent” coupon code. So, if acoupon code is located within the WORM it has already been spent. Thecurrent validated coupon code is not located on the WORM, the couponcode will be written to the WORM 2318 and the laser system will beauthenticated for treatment 2320.

Referring now to FIG. 24 , a system 2400 for authenticating a lasertreatment coupon, in accordance with one embodiment, is shown. Thesystem 2400 may include a processor 2420, a memory 2430, a userinterface 2440, a network interface 2450, and storage 2460, allinterconnected via one or more system buses 2462. It will be understoodthat FIG. 24 constitutes, in some respects, an abstraction and that theactual organization of the system 2400 and the components thereof maydiffer from what is illustrated.

The processor 2420 may be any hardware device capable of executinginstructions stored on memory 2430 and/or in storage 2460, or otherwiseany hardware device capable of processing data. As such, the processor2420 may include a microprocessor, field programmable gate array (FPGA),an application-specific integrated circuit (ASIC), or other similardevices.

The memory 2430 may include various transient memories such as, forexample L1, L2, or L3 cache or system memory. As such, the memory 2430may include static random access memory (SRAM), dynamic RAM (DRAM),flash memory, read only memory (ROM), or other similar memory devicesand configurations.

The user interface 2440 may include one or more devices for enablingcommunication with system operators and other personnel. For example,the user interface 2440 may include a display, a mouse, and a keyboardfor receiving user commands. In some embodiments, the user interface2440 may include a graphical user interface. The user interface 2440 mayexecute on a user device such as a PC, laptop, tablet, mobile device, orthe like.

The network interface 2450 may include one or more devices for enablingcommunication with other remote devices. The network interface 2450 mayalso allow for downloading of updates to software applications or known“spent” coupon identifiers. For example, the network interface 2450 mayinclude a network interface card (NIC) configured to communicateaccording to the Ethernet protocol. Additionally, the network interface2450 may implement a TCP/IP stack for communication according to theTCP/IP protocols. Various alternative or additional hardware orconfigurations for the network interface 2450 will be apparent.

The storage 2460 may include one or more machine-readable storage mediasuch as read-only memory (ROM), random-access memory (RAM), magneticdisk storage media, optical storage media, flash-memory devices, writeonce read many (WORM) memory, or similar storage media. In variousembodiments, the storage 2460 may store instructions for execution bythe processor 2420 or data upon which the processor 2420 may operate.

For example, the storage 2460 may include instructions to read amachine-readable code 270; verify the machine-readable code 2472; and,perform a laser treatment 2474. Instructions for performing the lasertreatment may include instructions to: generating, using a laserarrangement, a laser beam; directing, using an optical arrangement, thelaser beam toward a dental hard tissue; and, controlling, using a lasercontroller, a parameter of the laser beam in order to heat at least aportion of a surface of the dental hard tissue to a temperature above400° Celsius.

The instructions may additionally include preventing future verificationof the machine readable code. The instructions for preventing futureverification of the machine-readable code may include one or more ofbroadcasting to a ledger, submitting to a coupon authority, destroyingthe machine-readable code, writing to a write once read many (WORM)memory, and overwriting the machine-readable code

The instructions for verifying the machine-readable code 2472 mayinclude one or more of querying a ledger, broadcasting to a ledger,decrypting the machine-readable code, recognizing a digest within themachine-readable code, querying a write once read many (WORM) memory,and querying a coupon authority.

The instructions may additionally include measuring a laser variableduring the laser treatment. The laser variable may include one or moreof a duration of laser treatment, an electrical energy delivered to thelaser source during laser treatment, and a relative measure of laserenergy generated by the laser source during laser treatment.

The methods, systems, and devices discussed above are examples. Variousconfigurations may omit, substitute, or add various procedures orcomponents as appropriate. For instance, in alternative configurations,the methods may be performed in an order different from that described,and that various steps may be added, omitted, or combined. For example,in some embodiments, fluoride treatment is omitted after lasertreatment. Also, features described with respect to certainconfigurations may be combined in various other configurations.Different aspects and elements of the configurations may be combined ina similar manner. Also, technology evolves and, thus, many of theelements are examples and do not limit the scope of the disclosure orclaims.

Embodiments of the present disclosure, for example, are described abovewith reference to block diagrams and/or operational illustrations ofmethods, systems, and computer program products according to embodimentsof the present disclosure. The functions/acts noted in the blocks mayoccur out of the order as shown in any flowchart. For example, twoblocks shown in succession may in fact be executed substantiallyconcurrent or the blocks may sometimes be executed in the reverse order,depending upon the functionality/acts involved. Additionally, oralternatively, not all of the blocks shown in any flowchart need to beperformed and/or executed. For example, if a given flowchart has fiveblocks containing functions/acts, it may be the case that only three ofthe five blocks are performed and/or executed. In this example, any ofthe three of the five blocks may be performed and/or executed.

A statement that a value exceeds (or is more than) a first thresholdvalue is equivalent to a statement that the value meets or exceeds asecond threshold value that is slightly greater than the first thresholdvalue, e.g., the second threshold value being one value higher than thefirst threshold value in the resolution of a relevant system. Astatement that a value is less than (or is within) a first thresholdvalue is equivalent to a statement that the value is less than or equalto a second threshold value that is slightly lower than the firstthreshold value, e.g., the second threshold value being one value lowerthan the first threshold value in the resolution of the relevant system.

Specific details are given in the description to provide a thoroughunderstanding of example configurations (including implementations).However, configurations may be practiced without these specific details.For example, well-known circuits, processes, algorithms, structures, andtechniques have been shown without unnecessary detail in order to avoidobscuring the configurations. This description provides exampleconfigurations only, and does not limit the scope, applicability, orconfigurations of the claims. Rather, the preceding description of theconfigurations will provide those skilled in the art with an enablingdescription for implementing described techniques. Various changes maybe made in the function and arrangement of elements without departingfrom the spirit or scope of the disclosure.

Having described several example configurations, various modifications,alternative constructions, and equivalents may be used without departingfrom the spirit of the disclosure. For example, the above elements maybe components of a larger system, wherein other rules may takeprecedence over or otherwise modify the application of variousimplementations or techniques of the present disclosure. Also, a numberof steps may be undertaken before, during, or after the above elementsare considered.

Having been provided with the description and illustration of thepresent application, one skilled in the art may envision variations,modifications, and alternate embodiments falling within the generalinventive concept discussed in this application that do not depart fromthe scope of the following claims.

What is claimed is:
 1. A system for preventative dental treatmentcomprising: a laser arrangement configured to generate a laser beamhaving transverse ring mode, wherein the laser arrangement comprises abeam shaper, including one or more of an axicon, a spatial filter, adeformable mirror, and an annular slit, configured to shape the laserbeam into the transverse ring mode; a focus optic configured to convergethe laser beam with a numerical aperture less than 0.1 to a focalregion; a hand piece configured to direct the laser beam at a surface ofa dental hard tissue; and, a controller configured to control one ormore parameters of the laser beam, such that a portion of the surface ofthe dental hard tissue is heated to a temperature in a range of 400° C.and 1300° C.
 2. The system of claim 1, wherein the hand piece furthercomprises a turning mirror positioned down beam from the focus optic,configured to reflect the converging laser beam toward the dental hardtissue.
 3. The system of claim 1, wherein the laser beam has awavelength in one or more of a first range of 200 to 500 nm and a secondrange of 4,000 to 12,000 nm.
 4. The system of claim 1, wherein the laserarrangement further comprises one or more of an intra-cavitypolarization generator and a polarization converter.
 5. The system ofclaim 4, wherein the laser beam has a polarization that comprises one ormore of circular, radial, tangential, and azimuthal.
 6. The system ofclaim 1, wherein the one or more parameters of the laser beam compriseone or more of repetition rate, pulse energy, pulse duration, averagepower, peak power, and wavelength.
 7. The system of claim 1, furthercomprising a beam scanning system configured to scan the focal regionover a portion of the surface of the dental hard tissue.
 8. The systemof claim 1, wherein the transverse ring mode has an inner diameter thatis 50% or less than its outer diameter.
 9. The system of claim 1,wherein the transverse ring mode is a transverse electromagnetic (TEM)01* mode.
 10. The system of claim 1, wherein the focus optic has a focallength that is greater than 100 mm.
 11. The system of claim 1, whereinthe laser arrangement comprises a laser source having an intra-cavitydevice configured to generate the transverse ring mode.
 12. The systemof claim 1, wherein the laser arrangement comprises a laser sourcehaving an intra-cavity device configured to control a power of the laserbeam.
 13. A method for preventative dental treatment comprising:generating, using a laser arrangement, a laser beam having a transversering mode, wherein generating the laser beam having the transverse ringmode comprises shaping, using a beam shaper, the laser beam into thetransverse ring mode, wherein the beam shaper comprises one or more ofan axicon, a spatial filter, a deformable mirror, and an annular slit;converging, using a focus optic with a numerical aperture less than 0.1,the laser beam to a focal region; directing, using a hand piece, thelaser beam at a surface of a dental hard tissue; and, controlling, usinga controller, one or more parameters of the laser beam, such that aportion of the surface of the dental hard tissue is heated to atemperature in a range of 400° C. and 1300° C.
 14. The method of claim13, further comprising reflecting, using a turning mirror, the laserbeam toward the dental hard tissue; wherein, the turning mirror ispositioned down beam from the focus optic.
 15. The method of claim 13,wherein the laser beam has a wavelength in one or more of a first rangeof 200 to 500 nm and a second range of 4,000 to 12,000 nm.
 16. Themethod of claim 13, wherein the laser arrangement further comprises oneor more of an intra-cavity polarization generator and a polarizationconverter.
 17. The method of claim 16, wherein the laser beam has apolarization that comprises one or more of circular, radial, tangential,and azimuthal.
 18. The method of claim 13, wherein the one or moreparameters of the laser beam comprises one or more of repetition rate,pulse energy, pulse duration, average power, peak power, and wavelength.19. The method of claim 13, further comprising scanning, using a beamscanning system, the focal region over a portion of the surface of thedental hard tissue.
 20. The method of claim 13, wherein the transversering mode has an inner diameter that is 50% or less than its outerdiameter.
 21. The method of claim 13, wherein the transverse ring modeis a transverse electromagnetic (TEM) 01* mode.
 22. The method of claim13, wherein the focus optic has a focal length that is greater than 100mm.
 23. The method of claim 13, wherein generating the laser beamcomprises generating the transverse ring mode using a laser sourcehaving an intra-cavity device.
 24. The method of claim 13, whereingenerating the laser beam comprises controlling a power of the laserbeam, using a laser source having an intra-cavity device.